Product Review: Leica Trinovid BCA 8 x 20.

To establish ‘Limes.’

Back in the summer of 2019, I got the opportunity to test out a very high quality Swarovski EL Range 10 x 42 owned by a fellow villager named Ian. A keen hunter, he uses this binocular to seek out red deer and estimate their distance using the built-in laser telemetry in the instrument. A few weeks ago, I bumped into Ian in the swing park near my home, where he was looking after his young grandaughter, and we struck up another conversation about binoculars. I was returning from one of my walks,  carrying along my little Zeiss Terra 8 x 25 pocket. He was fascinated with this new instrument, being duly impressed with its razor sharp optics, generous wide field, light-weight ergonomics and decent market value. It was then that I discovered that Ian was also the proud owner of a little Leica Trinovid BCA 8 x 20, which he purchased about two years back for casual sightseeing during his summer vacations in the Scottish northwest. Keen to expand my portfoIio of tested instruments, I asked him if he would be kind enough to let me borrow it  for a wee while to evaluate its optical and mechanical performance. He agreed, but did say that he found the Terra to be very comfortable to use and was even considering acquiring one in the future! Fast forward a couple of weeks and Ian dropped by the Leica binocular at my home so that I could begin some tests, the results of which, I will divulge in this blog.

Leica is a German optical firm that has established itself as a world-leading manufacturer of high-end cameras, microscopes, camera lenses, binoculars and spotting ‘scopes for the burgeoning sports optics market. Founded in 1869 by Ernst Leitz, at Wetzlar, Germany, where the original factory remained until 1986, after which time production was moved to the town of Solms to the west of Wetzlar.  In 1973, Leitz set up another large factory in  Portugal, where it has remained to this day. With 1800 employees, Leica has an annual turnover of the order of 400 million Euro, and continues to produce state-of-the art optical equipment for private and public institutions(mostly universities and hospitals) the world over.

The Leica Trinovid line of binoculars has a long history. Leica first began to manufacture high-quality binoculars back in 1907, but the Trinovid line first appeared in 1953. Over the years, Leica has continued to develop their Trinovids, adding new optical technologies to their products where, today, they utilize some of the best glass and optical coatings available.

First Impressions

The quality of the device was immediately apparent to me as I prized the 8 x 20 from its somehwat oversized, soft carry case. Weighing in at just 235g, the Leica Trinovid BCA 8 x 20 measures just 9cm long, 6cm wide and 3.5cm deep when folded up. This makes it one of the smallest and most portable binoculars in continuous production today.

The Leica Trinovid BCA 8 x 20(made in Portugal) folds up into a tiny storage unit just 9cm long and 6cm wide. Note the unusual location of the right eye dioptre setting, which is accessed by turning the objective lens housing.

The binocular has a very traditional dual-hinge system but maintains a very classic look and feel, with an aluminium frame. Unlike their larger binoculars, the BCAs are described as ‘splashproof’, meaning that they will work fine in rainy conditions but are not hermetically sealed or dry nitrogen purged like the majority of roof prism binoculars today. The all-metal chassis is overlaid by a tough rubber armouring, which greatly improves its grip during field use and affords greater protection against accidental bumping or knocking about.

The strong and durable rubber armouring overlaying the aluminium chassis of the Leica Trinovid BCA 8 x 20.

The eyepieces are of exceptionally high quality, being made of metal overlaid by soft rubber cushions for comfortable viewing. They offer just two positions; fuly extended upwards for non-eyeglass wearers(including yours truly) or fully retracted when used with glasses. Eye relief is pretty tight though, at just 14mm, so some eyeglass wearers may struggle seeing the full field. The eyecups hold their position very well and can only be retracted by using considerable downward force. I must say that these are the finest eyepieces I have thus far experienced in my survey of the binocular market. Simply put, they are beautifully designed.

The beautifully designed eyepieces click rigidly into place.

Intriguingly, the dioptre setting(+/-3.5) is located on the right objective lens, which turns either clockwise or anti-clockwise. The focus wheel, which appears to be constructed of a hard plastic, is quite small but moves very smoothly with zero backlash. At first, it’s a bit fiddly to use but with a little practice becomes easier to negotiate, though it may present problems to those who wear gloves.  All in all, the binocular is a study in elegant design. Clearly it was created not only to look good but to feel good in active service.

The Trinovid BCA has a high-quality, somewhat elastic, neckstrap, which is affixed via clips, so can be disengaged from the binocular if so desired. It is comfortable to use. Yet again, an unusual but very nice touch.

The objective lenses are not very deeply recessed in this model, perhaps because its designers aimed to minimise the length of the instrument. Having more deeply recessed objectives serves a number of useful purposes though, including protection against rain and dust, and serving well as an effective barrier against peripheral glare.

The objective lenses on the Trinovid are not very deeply recessed.

Optical Testing

As is customary for me with the arrival of any new binocular for testing, I began by assessing its performance in suppressing stray artificial light, internal reflections and glare. This is easily done by sharply focusing on a bright internal light source – I use my iphone torch at its brightest setting – in a darkened room and sharply focus on the light. Such tests quickly revealed highly satisfactory results. Stray light was very well controlled and very clean, with only very minor internal reflections and no sign of diffused glare often encountered in lesser models. The main artefact was a reasonably pronounced diffraction spike. Indeed, using two small ‘control’ binoculars; my Zeiss Terra 8 x 25 pocket and my recently acquired Celestron Trailseeker 8 x 32 (both of which exhibit excellent performance in this regard), I judged the Leica 8 x 20 to be as good, if not a little better, than my controls. All of these binoculars employ full, broadband multi-coated optics on all glass surfaces, with prisms that are dielectrically coated for highly efficient light transmission. The results predict that the Leica will perform excellently when pointed at strongly backlit daylight scenes, bright street lights and bright terrestrial targets like the Moon. There is no such thing as absolute perfection though. Such a complex optical device will always betray some degree of imperfection under these very stringent tests. I guess, it just comes with the territory!

The high quality HDC coating makes for exceptional light transmission.

In good accord with my flashlight tests, pointing the little Trinovid at a bright sodium street light at night showed no internal reflections, glare and only a very faint diffraction spike that I didn’t find intrusive. These tests were followed up by daylight optical assessments. Looking at tree trunks and branches during bright afternoon conditions showed that this 8 x 20  has excellent optics with a good, wide field of view. The image is tack sharp with a very large sweet spot. There is only slight softening of the images in the outer 10 per cent of the field. Colours are true to form and I detected only the merest trace of chromatic aberration and then only by looking very hard for it(I honestly find this activity rather pointless) on difficult targets. Contrast is exceptional with excellent control of stray light, as judged by imaging targets nearby a setting Sun under hazy sky conditions. There is a normal level of veiling glare which can be removed by blocking the Sun with an outstretched hand. There is also some minor pincushion distortion at the edge of the field but I still judged this to be well above average.

Excellent coatings make the objectives almost disappear.

Some readers will be surprised to learn that Leica did not employ any ED elements in the objective lenses of their BCA binoculars, proving once again that such an addition is not at all necessary to create an excellent optic(the Swarovski CL pocket and larger sibling, the CL 8 x 30 Companion are yet other examples). What really matters are well figured glass elements with high-quality anti-reflection coatings. Looking up its specifications online showed that Leica has spared no expense applying their famous(patented) High Durable Coating (HDC). It purports to be abrasion-resistant with enhanced light transmission, and then there’s the solid P40 dielectric phase coating applied to the Schmidt-Pechan roof prisms. What results is a highly efficient light gathering optic; an especially important commodity for tiny binoculars like these.

The Trinovid certainly delivers optically when the light is good and strong. But it does have some issues which are important to address. Because of its very small size, it’s actually quite challenging to hold steady during field use. It’s small exit pupil (2.5mm) also makes it considerably more difficult to position one’s eyes correctly compared with slightly larger binoculars, such as a good 8 x 25( with a 3.125mm exit pupil). Comparing its ergonomics with my Zeiss Terra 8 x 25 pocket glass showed that the Terra was simply much easier to engage with even though it’s only about 30 per cent heavier(310g). It’s larger frame also gives it the edge in terms of acheiving a good, stable image. This could prove important if the owner intends to use the 8 x 20 BCA for prolonged glassing periods, as the extra effort incurred in accurately positioning one’s eyes over the small exit pupils may induce eye strain with some users, so I think it’s important that people seriously considering this tiny glass try the more popular 8 x 25 units out before making that all-important purchase. Indeed, I believe this point was not lost on Ian when he tried the Terra out in the swing park that afternoon.

In an ongoing blog on using my 8 x 25 binos, I gave mention to why I think good pocket binoculars are quite expensive in the scheme of things. I attributed this to the extra difficulty in accurately positioning the many optical components stably within a scaled-down structure. The Leica Trinovid BCA 8 x 20 seems to follow this rule of thumb. It is smaller than any 8 x 25 model but is also more expensive(about £350 to £400 UK as opposed to £270 for the Zeiss Terra 8 x 25, for example). But there is surely folly in pursuing this to its logical conclusion. For example, would it be sensible to create an even smaller, state-of-the-art 15mm model say, that can fit on two fingers and cost £500?

Of course not! That would be daft. It would be too small and fiddly to use and the amount of light it would bring to one’s eyes- even if it were 100 per cent efficient – would severely limit its use. That’s probably why the other premium binocular manufacturers – particularly Zeiss and Swarovski – have discontinued their 8 x 20 models in favour of 8x and 10 x 25mm units. Indeed, all of this has close parallels to the premium, small refractor market, where folk seem to pay exorbitant prices for tiny, albeit perfect, optics. Is that really sensible? Not in my mind – which is why I turned my back on it- but your mileage may vary!

Assorted notes:

The Leica Trinovid BCA 8 x 20 has ocular lenses just a little smaller than its objective lenses.

The instrument comes with a ten year warranty.

Each Leica binocular comes with a test certificate which claims that it was tested at various times during its manufacture prior to leaving the factory.

The Leica mini-binocular didn’t appear to come with caps, either for the objectives or eyepieces. It does just fit the small Opticron branded rainguard for compact binos however, which I use with my 8 x25s.

It is hard to find the ‘made in Portugal’ stamp on the Leica. But it is there, stealthily placed under the left barrel of the optic, and only accessed by fully extending the instruments IPD to its maximum where you’ll see: Designed by Leica Portugal.

The Opticron-branded rainguard I use for my 8x 25s just fits the smaller leica binocular.

More info on this package here.

Comparison with other Premium Pocket Binoculars

The Leica Trinovid BCA 8 x 20(left)versus with the Zeiss Terra 8 x 25(right). Note the latter’s larger frame and bigger focus wheel.

I spent a few hours comparing and contrasting the Zeiss Terra ED 8 x 25 and the Leica BCA 8 x 20 during bright sunny conditions(for January) and again under dull overcast conditions, as well as looking for performance differences at dusk, when the light rapidly fails afer sunset.

Under bright sunny conditions there was not much difference between both binoculars in terms of optical performance(both are excellent in this regard), except that the Zeiss has a noticeably wider field of view(119m compared with 110m@1000m). Because of its larger frame, larger focus wheel and larger exit pupil, the Zeiss proved easier to handle and  easily rendered the more comfortable, immersive view. The weight difference between these instruments is only 75g, so I don’t think many folk would quibble about the increase in bulk mass.

Under dull overcast conditions, the Zeiss produced a slightly brighter image, which became more and more pronounced as the light began to fade after sunset(around 5pm local time in the last week in January). This ought not surprise anyone, as both binoculars are highly efficient light gatherers and so simple physics dictates that the larger 25mm glass wins.

Close focus on the Leica was estimated to be about 1.8 metres, significantly longer than the Zeiss Terra at 1.4 metres.

Comparison under the Stars

The differences between the 25mm glass and its 20mm counterpart was most pronouced when aimed at the night sky. The larger exit pupil and aperture on the Zeiss Terra pocket allowed me to see significantly fainter stars around Orion’s belt and in the Hyades, compared with the Leica. At first I judged the contrast to be slightly better in the Leica than in the Zeiss but upon reflection, I attribute this to the smaller exit pupil in the former, which naturally generates a darker sky hinterland. The wider field of view in the Zeiss also helps frame objects that little bit better than the Leica. So, for casual stargazing the Zeiss proved noticeably superior to the Leica 8 x 20. I would not really recommend the 8 x 20 for such activities over a larger glass. But neither should anyone expect miracles here. The Leica is designed for daylight use in the main, although one can always enjoy the odd look at the Moon with the 8 x 20 when it is present in the sky.

Comparisons to a Celestron Trailseeker 8 x 32 Compact Binocular

How does the Leica Trinovid BCA 8 x 20 compare with a good 8 x 32 compact binocular?

Comparing a mid-sized, semi-compact binocular like the Celestron Trailseeker 8 x 32 with a diminutive 8 x 20 might seem a little out of place. But I think its inclusion is valid. The Trailseeker is very light; indeed, at just 453g, it ranks as one of the lightest 8 x 32s on the market, but still has many mechanical and optical features that only a few years ago were the preserve of premium binoculars; a magnesium alloy chassis, solid, well-designed metal-under rubberised adjustable eyecups, fully broadband multicoatings, dielectrically coated Bak-4 prisms et cetera.

Comparing the images served up by both the Celestron and the Leica in bright daylight in the open air, my wife and I both concluded that the Leica has slightly better contrast and sharpness across much of the field than the Celestron 8 x 32. Edge of field performance is also significantly better in the Leica. But we also agreed that the Celestron was more comfortable to use, owing to its larger exit pupil (4mm). That said, we also reached the conclusion that the Celestron binocular rendered a slightly brighter image even in good light. But while there are perceptible differences between the two instruments, it must be stressed that these differences are small and subtle. Of course, that conclusion will likely upset a few of the more pestiferous premium bino junkies out there, but it is nonetheless true in our experience. The Celestron held its own very well indeed against the sensibly perfect Leica.

But there is considerably more to say about the economical Trailseeker. Move from the open air into a heavily canopied forest or copse and the advantages of the larger aperture binocular become much more apparent. Under these conditions, the Celestron fairs a lot better, delivering brighter images and more information to the eye. And as the light diminishes in the late afternoon, the Celestron clearly pulls ahead, as it ought to do, owing to its much greater light gathering power. At dusk, the differences between the two models are literally like night and day. Under these conditions, the 8 x 32 Trailseeker is vastly superior. It doesn’t matter if the optics in the Leica are sensibly perfect when you can’t see those details.

You see, the little Leica is like an elastic band – stretch it too far and it will break!

The same was true when pointing both binoculars at the night sky. After struggling to peer through the Leica, the Celestron was pure joy!  Its very efficient light transmission(~ 90 percent) and much wider field of view (7.8 degrees) brings so much more of the Universe to your eye!

These results helped us both to appreciate just how good the Chinese-made Celestron Trailseeker 8 x 32 really is. At roughly one third of the UK price(recently reduced to half its originanl market value(~£250) for clearance) of the Leica, we’d both say that it delivers 90 per cent of the bright, daytime performance of the Leica and vastly superior low light and night time performance. In many ways, this small and light-weight 8 x 32 is a more versatile performer than the 8 x 20 Leica Trinovid BCA, and those wishing to use their binoculars in more compromised lighting conditions would probably be better served with a good instrument in this size class.

And I have to ask this question again: is a weight of 453g really anathema to those who want to travel ultra-light?

nota bene: these comments regarding the Celestron Trailseeker 8 x 32 are also applicable to the previous discussion of my Zeiss Terra pocket glasss, in case you’re wondering.

These tests affirmed the excellent bang-for-buck the Celestron Trailseeker really represents. Veteran binocular enthusiast and fellow author, Gary Seronik, is dead right in highlighting these recent trends: mass produced, Chinese-derived optics are now coming so awfully close to premium performance-both optically and mechanically – that I would have reservations shelling out much more of my hard-earned cash just to get slightly better optical performance and the right to brag! For these reasons, I’m very pleased with and have no plans to upgrade the 8 x 32 Celestron; it will remain as part of my binocular stable.

To be continued…………………….

 

De Fideli.

What I’m Reading.

Educating the pond scum merchants….ken.

Paperback: £19.09

486 pages.

The origin of life from non-life remains one of the most enduring mysteries of modern science. The Mystery of Life’s Origin: The Continuing Controversy investigates how close scientists are to solving that mystery and explores what we are learning about the origin of life from current research in chemistry, physics, astrobiology, biochemistry, and more. The book includes an updated version of the classic text The Mystery of Life’s Origin by Charles Thaxton, Walter Bradley, and Roger Olsen, and new chapters on the current state of the debate by chemist James Tour, physicist Brian Miller, astronomer Guillermo Gonzalez, biologist Jonathan Wells, and philosopher of science Stephen C. Meyer.

Some Initial Endorsements:

“Cogent, original, compelling.”–Dean Kenyon, Professor Emeritus of Biology, San Francisco State University

“An important contribution to the origin of life field.”–Robert Shapiro, Professor Emeritus of Chemistry, New York University and author of Origins: A Skeptic’s Guide to the Creation of Life on Earth

“A valuable summary of the evidence against the chemical evolution of life… very well thought-out and cleary written.”–Robert Jastrow, founding director of NASA’s Goddard Institute for Space Studies

 

De Fideli.

Astronomy with a Pocket Binocular.

Creating a new genre of amateur astronomy literature.

A work commenced November 11, Anno Domini 2019.

Subject to Copyright

I’m a big fan of pocket binoculars; they’re tiny, elegant, and when decently made, are  very sharp shooters. Compared with standard-sized binoculars, ‘pockets’ are much less expensive and there is a good one available to suit most anyone’s budget. They can work well with kids, grand-parents and every one in between. Their extreme portability makes them very popular across a broad ecclesia of people; hikers, birders, sports spectators, hunters, theatre goers and general nature lovers. They’re as likely to be found near a window overlooking a garden as they are tucked away in a backpacker’s pouch. But what is less commonly known is that they can be used for casual astronomical viewing. Unlike telescopes, there is no set up required. Simply pick it up and off out you go! They’re so small that they are completely immune to the vagaries of the Earth’s atmosphere. It doesn’t matter if the seeing is horrid or immaculate, their small apertures and low magnification will show you the same view, under the same conditions, time and time again. Their very low carrying weight allow individuals to hold them to their eyes much longer than standard binoculars in the 40 to 50mm aperture class. And as soon as you’re done, they fold away in a pocket, hence the name.

Pocket binoculars are almost invariably not recommended for astronomy. Sure, they don’t provide those knock-out views you get with larger binos, but what if your only instrument were a pocket binocular? Is viewing the night sky anathema? Absolutely not! Even small glasses like these can bring a great deal of cosmic real estate to your eyeballs. And though their ability to gather faint starlight is limited, they will nonetheless greatly exceed the acuity of even the keenest, sharpest human eye.

I suspect that one of the main reasons why pocket binoculars are not spoken of much in astronomical circles is that most people live in big cities or towns, where light pollution drowns out much, if not all, the glory of the starry heaven. They are disconnected from the great natural light show provided by Amighty God, who reveals His majesty in every shooting star, every burning sun, every moon, planet, and galaxy scattered across the Universe. But if you take leave of the cities and drive out into the countryside, the night sky is transformed from a washed-out, featureless dome into a marvellous light show that can fill us with awe and re-unite us with the sacred, the mysterious and the infinite-eternal.

I have the immense good fortune to live in a beautiful place, far enough away from the large cities and towns that are home to the vast majority of people. I can step out of my back door and immediately engage with the sky. I take nothing for granted. For me, astronomy is not always connected with darkness. In Scotland, we enjoy many fabulous sunsets, painting radiant colours; brilliant oranges, sanguine reds, and even purple splashes across the heavens as the Sun makes its way toward the horizon. As dusk gives way to darkness, the night sky has a way of wrapping itself around you like a magic cloak. At first, only the brightest stars can be seen, but as full darkness falls upon the landscape, the great host of heaven come out to play. Being located on the western edge of northern Europe, beautiful auroral displays are common, colouring in the northern horizon in magnificent ribbons of incandescent light. Out here in the sticks, the great river of stars that constitute the Milky Way can be easily seen on a dark, Moonless night.

During  deepest winter, darkness rules. The Sun sets early(4pm) and rises late(8am). Many go to work in darkness and travel home in darkness. Yet in summer, the Sun rules the sky from 3.30am to after 9pm, and even then its shallow dip below the northeastern horizon never brings true darkness. In June and July, twilight rules the wee small hours. Still, whether it’s high summer or deepest winter, my pocket binoculars never fail to show me something new and exciting.

A mid-Summer’s night stroll; looking northeast at 2 minutes after midnight on June 22, 2019.

My quest to find a good pocket binocular encountered many unexpected twists and turns. I don’t live anywhere near a good binocular dealer, so I was not afforded the luxury of ‘trying before you buy,’ as it were. No, in my case, the best I could do was ‘buy-in and try.’ Some models promised the earth but fell well short of the mark. In other cases, I trusted the opinions of a number of so-called ‘experienced glassers’, but upon learning how to test such instruments myself, I discovered that many of these reviews were just not discriminating enough. It was like deja vu all over again from my telescope testing days( I have no interest in acquiring any new telescopes, as I already have all I could possibly wish for). Some models advertised as ‘premium’ turned out to be junk.

Premium junk.

In the end though, I settled on a couple of models – both 8 x 25  formats – made by reputable firms; Zeiss and Opticron. Unlike a swathe of pretenders, these were the real McCoys. Both models are very well made, with fully-multicoated optical components and phase corrected Schmidt-Pechan roof prisms. The Opticron has a wonderfully flat field of view, thanks to the incorporation of aspherical ocular lenses, but the size of the field is rather restricted as modern pocket binoculars go; just 5.2 angular degrees. In contrast, the Zeiss Terra has a significantly wider field – 6.8 degrees – but is not quite as sharp at the edges of the field as the Opticron. During daylight testing, I ascertained that the Zeiss Terra produced a slightly brighter image, due in most part to the employment of higher reflectivity dielectric coatings on the prisms. The Opticron, in contrast, has silver coated prisms, with slightly lower reflectivity.

My instruments of choice; the Zeiss Terra(left) and the Opticron Aspheric LE(right).

Both models display excellent control of stray light and do not produce annoying internal reflections and glare when pointed at bright objects like the full Moon, or during the day, when glassing strongly backlit scenes. This affords the highest levels of contrast in the images they produce. For astronomical use, where all the objects are effectively located at infinity, it is important for the field to remain as flat as possible from the centre right the way to the edge for aesthetic appeal. While many of the pretenders I tested were good on axis, their edge of field definition was less than desirable. And no one wants to see stars bloat to enormous sizes as they are moved off axis.

Both models have hermetically sealed optics, filled with dry nitrogen gas at a slighly higher pressure than the surrounding atmosphere. This prevents fogging of the optics in cold weather and slows down internal corrosion of the components. The slight pressure differential also creates a small outward force that helps keep dust and fungi  from entering the instruments. Ergonomically, the Zeiss is easier to use, as its slightly larger frame fits my hands that little bit better than the Opticron. Both focusers are buttery smooth with zero backlash when rotated clockwise or anti-clockwise, but this has proven more important during daylight observing than at night, where relatively little focusing adjustments are required, as for example, in moving from a target at low to high elevations above the horizon. The Opticron is the more elegant instrument; the Zeiss more rugged.

Mechanically, both the Zeiss and Opticron are very well endowed. The double-hinge design on both models has enough tension to maintain my particular inter-pupillary distance, and fold up with ease when not in use. The eye lenses are good and large on both instruments, allowing me to comfortably and swiftly engage with the entire field, with little or no guesswork or blackouts. The eyecups on both instruments are robust, comfortable and simple to deploy. Unlike other models which offer several positions, both the Zeiss and the Opticron only have two- either fully down or fully up. So, not a lot to think about, you’re either in or you’re not.

And both have the same eye relief; 16mm.

The Zeiss Terra Pocket(right) is a little wider and taller than the more conventional Opticron Aspheric(left), but both fold away when not in use.

The larger field of view of the Zeiss(6.8 degrees) is more useful for daytime applications, but at night, when observing the sky, even a 5.2 degree field is more than sufficient to frame the vast majority of targets I’m likely to study. I estimate that the limiting magnitude of both instruments to lie somewhere between +8.7 and +8.9. And with the same exit pupil – 3.1mm – they allow me to image targets with the sharpest part of my well designed eye lenses.

A Walk through the Autumn Sky:

A favourite autumn  haunt.

November is perhaps my favourite month. It’s easy enough to justify. I entered the world in November, and have come to associate my experiences of it with the carefree days of my youth. While the trees begin their long winter slumber, I feel especially alive. All my senses go into overdrive. Maybe it’s the vibrant colours of autumn leaves that assault the eyes, or the sweet, musky aroma of decaying plant matter that infuses the misty air. Or could it be the crunching sound made by my feet as they wade through the rain-soaked leaf litter that creates a memory trace back to the innocence of childhood? Whatever it is, walking though the rural autumn landscape upwells deep feelings of reverence for the preternatural beauty of the wet and the wild.

The feeble light of November compels me to re-schedule the times of my walks, and usually I try to make the most of the daylight by venturing out around noon, when the Sun is at its highest in the sky. And though November nights can be mild, bitterly cold, and everything in between, the celestial treasures that attend a clear night with no Moon greatly warm the heart.

To help us find them, it pays to invest in a good literary guide and, in this capacity, I would heartily recommend  Ian Ridpath’s and Wil Tirion’s, Collins Stars & Planets, now in its fifth edition. In it the student of the starry heaven can find all kinds of useful information, packed full as it is with month-by-month maps of the entire night sky, as well as beautifully illustrated colour maps of all 88 constellations that grace the celestial sphere.

Good companions under the stars.

Heralds of Winter

So without further ado, let’s begin our adventures with a pocket binocular. A great place to start is to seek out two amazing sights in the northern heavens; the glimmering Pleiads and imposing Hyads, both located near each other, and both well situated for observation, riding high in the sky after 9pm on mid-November evenings.

The constellation of Taurus.

Before we embark on our first celestial adventure, let’s get suitably attired  by reading the  celestial swangsong of Lord Byron(1788-1824):

‘Tis midnight! on the mountains brown

The cold round moon shines deeply down;

Blue roll the waters, blue the sky

Spreads like an ocean hung on high

Bespangled with those isles of light,

So wildly, spiritually bright.

Whoever gazed upon them shining,

And turn’d to earth without repining,

Nor wish for wings to flee away,

And mix with their eternal ray?

From Night at Sea by Lord Byron.

Both the Pleiades and Hyades, the heralds of winter, are easy to find in the November night sky. Both are located in the zodiacal constellation of Taurus. The Hyades is readily identifiable as a distinctive V-shaped asterism with a bright orange coloured star, Aldebaran, marking the southeastern-most tip of its horns, and a little higher up and to the right of it you’ll see the glittering jewels of the Pleiades star cluster.  Known by many names throughout antiquity and even further back into the long human pre-history, the Pleiades appears as a tiny congregation of stars, rather like a miniature Plough with a somewhat truncated handle. For me, the most inspiring references to the Pleiades  are sourced from God’s very own love letter to humanity; the Holy Bible. In all, the gleaming Pleiads are mentioned three times in the Good Book, twice in Job (9:9 & 38:31) and once in Amos(5:8), where the King James Version mentions them as “the seven stars”. The Lord God Almighty challenges his servant, Job, by asking him if he can “bind the sweet influences of Pleiades?” The implication is clear; no human can do such a thing, but it’s all in a day’s work for his Creator.

With my average eyes, I can usually make only six members from my home. But at darker sites, with better transparency, I have occasionally chanced on the seventh member – whence its nickname of the Seven Sisters – though still with considerable difficulty. That said, there are many accounts of people seeing more than seven members with the naked eye. For example, from the summits of high mountains, where the air is thinner and (often but not always) less turbulent, reports of seeing as many as 10 or 12 members are not uncommon in the archives. I know of one account, published in the Astronomical Register from October 1883, where astronomers at the newly established Pic Du Midi Observatory in the French Pyrenees, at an elevation of about 9,500 feet, reported the detection of 16 members with the naked eye!

The Pleiades, as seen in the 8 x 25 pocket binocular.

Through the pocket binocular, the Pleiades never fails to inspire. Instead of straining to see six members, several dozen are plainly presented covering the central third of the binocular field. And though the view is immeasurably improved by looking through a larger binocular or small telescope, I cast my mind’s eye back in time to when the Italian astronomer, Galileo Galilei, first turned his primitive spy glass on the same cluster of stars in 1610. Though the field of view of his telescope was woefully small (about one quarter of an angular degree, or half a full Moon diameter), Galileo still managed to record the main stars of the cluster, which are spread across one and a half Moon diameters. That’s something I have done before when I was sketching the Double Cluster in Perseus using a large Maksutov Cassegrain, sporting a field of view of only half an angular degree. It’s challenging but it’s certainly doable!

The Pleiades, as drawn by Galileo Galilei in the winter of 1610. Image credit: Wiki Commons.

The number of stars visible in the Pleiades depends on a variety of factors; the amount of light pollution you encounter, the transparency of the air you’re looking through, as well as its elevation above the horizon. I find the latter factor particularly interesting, as I have watched the Pleiades from its heliacal rising in the east in the wee small hours of August nights, right the way through to late spring, when it is observed sinking ever lower in the west.  When the cluster is glassed close to the horizon, only the most brilliant members are clearly discerned with the pocket binocular. For example, when observed at just 10 degrees above the eastern horizon, the dense canopy of air you’re looking through will dim the brilliance of the cluster by nearly one stellar magnitude! But if you venture out later in the evening, when the cluster has reached say 30 degrees altitude, you’ll gain an extra half a magnitude and your little binocular will begin to to show many fainter members. So, the higher the cluster rises in the sky, the better the view you will experience. This is equally true of any astronomical target, so it always pays to wait until your binocular target is well above the horizon; patience is a virtue!

The brightest luminaries of the Pleiades have beautiful names, inspired by the mythology of classical antiquity; Merope, Pleione, Electra, Asterope, Maia, Celaeno, Alcyone, Taygeta and Atlas, which you can see on page 241 of my guide book referenced earlier. The pocket glass reveals that they all have a silvery white colour, that betrays their relatively young age, which astronomers estimate to be about 50 million years. The centre of the cluster is thought to be located at a distance of about 450 light years.

If the Pleiades fail to inspire, then surely the majestic Hyades can? To see it, cast your gaze at the bright orange star Aldebaran and bring the pocket glass to your eyes. What you will see is a large V-shaped asterism filling most the field of view of the pocket binocular. These are the ‘horns’ of the celestial Bull, with Aldebaran situated in the south east of the field. Like the Pleiades, the Hyades is also steeped in ancient Greek mythological lore(but mostly pagan). Indeed, the Hyades were the fabled daughters of Atlas and Aethra, and half-sisters of the Pleiades.

The Hyades(with the outlined V shape) as seen in the 8x 25 pocket binocular.

When situated high in the sky, the Hyades is a marvellous sight in the pocket binocular. If you take a long, studied look at it with dark-adapted eyes, you will begin to notice that there are other red stars in the field, specifically, the three brightest stars that delineate the upper(northernmost) horn of the Bull. Its other stellar constituents appear white or blue-white to my eyes.

In order to create more atmospheric scenes, it pays to seek out some trees over which the Hyades and Pleiades appear to hover. Even on a dark night, the silhouette of tree branches set against these illustrious autumn clusters can be easily made out and adds greater dimensionality to the binocular view. I also love to observe these clusters as they change their orientation in the binocular field, rising in the eastern hemisphere, culminating in the south, before falling back towards the western horizon.

Unlikely Twins

The constellation of Gemini as depicted on page 153 of the guide book.

By the time the Pleiades and Hyades have reached a good altitude in the sky, the constellation of Gemini will be seen rising above the eastern horizon. But just as the full Moon often appears larger to the naked eye when it is close to the horizon, the same is true of the relative positions of the stars. Though seldom(if ever?) discussed in the contemporary astronomical literature, the illusion is known as the horizon enlargement effect. This can be perceived rather easily when observing the two brightest luminaries of this constellation; Castor and Pollux. If you see these stars rising in the background of a distant landmark, such as a hill or a building, they will appear to be more widely separated than when they are situated higher up in the sky. The effect is quite dramatic, though still illusory. That said, the little pocket binocular always shows them to be the same distance apart, no matter where they are situated in the night sky!

This curious effect was discussed over a century ago in an interesting article penned by Dr. Edouard Claparede, which first appeared in the October 1905 edition of Archives de Psychologie, and which was subsequently discussed in a short communication published  in the journal Nature dated February 22nd 1906, in which it is stated:

He(Dr. Claparede) arrives at the conclusion that when we see the moon or sun, at the horizon, we are surprised into believing it to belong to things terrestrial – to come into the class of objects which are by far of the greatest interest to us. As such we notice it with much greater attention, and for this reason overestimate its size.

But there is yet more illusion associated with Castor and Pollux, the so-called celestial twins, than that presented by the horizon enlargement effect. Situated exactly 4.5 angular degrees(or 9 full Moon diameters) apart, both stars easily fit in the field of the view of my pocket binoculars, but if you look at their colours they will be seen to be completely different; Castor(located higher up in the sky) is white, pure as the driven snow, while Pollux(lower down) presents as orange in contrast. What is more, Pollux appears distinctly brighter in the pocket glass than Castor(and to the naked eye for that matter!), though their designation is opposite to what one might expect in that the brightest star in a given constellation is usually assigned the Greek letter alpha, and the second in glory, beta and so on. The reason lies squarely at the feet of the Johann Bayer(1572-1625) who wrongly assigned the Greek letters to these stars in 1603 in his magnum opus, Uranometria Omnium Asterismorum, seemingly unaware that Castor was fainter than Pollux. In fact, Castor, with a visual magnitude of + 1.6, is assigned to the second tier of stellar glory, while Pollux, at +1.1 is a bona fide 1st magnitude sun.

Curiosuly, Bayer’s blunder was not unique to his good self. Many celebrated astronomers through history estimated both stars to be of the same degree of glory(2nd magnitude); Hipparchus, Tycho Brahe and Hevelius, to name but a few. And closer to our own time, Argelander(1840) and Heis(1860) though accurately assigning Pollux to +1.1, designated Castor a value fully half a magnitude fainter than it really is (+2.1). Only with the invention of the photometer in the 1860s did these discrepancies become resolved.

Looking at these stars through the pocket binocular, or any other optical accoutrement for that matter, one is hopelessly unaware of their distances from the solar system, which astronomers have estimated to be 52 and 34 light years for Castor & Pollux, respectively. And neither could they realistically be expected to have been formed from the same stellar nursery. What is more, though the apparition is quite beyond the capabilities of these tiny binoculars, Castor is a fascinating multiple star system of which, the two most prominent are closely separated stars, designated A and B, both roughly three times the mass of the Sun and of an early spectral type A, with an estimated age of 370 million years. Through a small telescope at high magnification, they make a splendid visual target, easily resolved in this epoch(2019) in even a humble 60mm refractor.  Pollux on the other hand, is a more highly evolved orange giant star, nearly twice the mass of our Sun and of late spectral type K, with an age nearly twice that of its so-called twin(724 million years).- or should it be triplets?

What blessed illusions the stars rain down upon us!

A Field Full of Stars!

The stars of Perseus, with its brightest star, Mirfak. marked with a pencil tip.

Were you to venture outdoors after supper on a clear, late November evening, the constellation of Perseus, the celestial Hero, will be very well placed, high in the eastern sky, and easy to scrutinise with the pocket binocular. Now cast your gaze at its brightest luminary, Mirfak, bring the glass to your eyes, and you’ll be greeted by a remarkable sight; a field littered with a few dozen stars, ranging in brightness from the 2nd to the 8th magnitude of glory! The nearly flat fields presented by my chosen instruments make vewing this target an especially enjoyable experience, with pinpoint stars from centre to edge.

Known by various names, this remarkable congregation of suns is most often referred to as Melotte 20, after the Anglo-Belgian astronomer, Philibert J. Melotte(1880-1961). Better known for his photographic discovery of the eigth satellite of Jupiter, Melotte published a ground-breaking photographic atlas of the sky in 1915, wherein he numbered this curious stellar grouping. The eye, naturally enough, humanises the view; creating order out of the stellar chaos; almost effortlessly linking up the light years between its members, imbuing  them with a sense of the familiar; perhaps slithering serpents or great meandering rivers. If this were a typical telescopic scene, with its higher power and smaller field of view, you’d be easily fooled into thinking that this was a bona fide star cluster, bound up in a gravitational embrace like the comely Pleiads. No, the stars you pick up with the little pocket glass are not so much bound by gravity as they are by common velocity; they’re all moving in the same direction through space. And it was this discovery that led to the other appellation bestowed upon them; the Alpha Persei Association, thought be located about 600 light years from the solar system.

Melotte 20 as observed in the pocket binocular, mid-evening view looking high in the east.

The majority of its stars are young (50-70 million years) and of early spectral type O or B, explaining why many appear white or blue-white to my eye. And yet, if you concentrate your gaze on its brightest member, Mirfak, the pocket glass will soon convince you that it’s not merely white, but rather a creamy-white. And that comports with its spectral class; F5.

Mirfak is a very big star in the scheme of things; fully 8 or 9 times the mass of the Sun, and so destined to live fast and die young.

It is unquestionably more difficult to view Melotte 20 when it’s at its best position at my location, especially if you’re not inclined to lying on your back, observing it as it passes near the zenith later in the night. The early evening location of Melotte 20 will afford a more comfortable viewing experience in the pocket binocular. What’s more, I have enjoyed glassing it profitably under less fecund skies, from towns and even under the bright light of cities.

Unlike the Pleiades, the most prominent members of which have memorable names, most of the stars in Melotte 20 are only acknowleged with numbers. Yet the Old Book tells us that although it was allotted to Adam to name all of God’s creatures, the Lord knows all the stars intimately. As the Psalmist declares;

He telleth the number of the stars; he calleth them all by their names.

Psalm 147:4

And yet, mighty in the creation of its myriad blazing suns, is He no less mighty in giving life to a tender, green blade of grass upon the earth?

There’s no escaping. Near and far, everything lies within the span of His hand.

More Leopard than Lion

I am by temperament, solitary. Although I’m a fully committed family man, I am happy and content in my own company. I’ve always disliked crowds and spend the vast majority of my observing time alone with my instruments and my thoughts. Maybe it’s just about growing older.  In past years, I have attended some star parties, but found them more a distraction than anything else. My days of hooking up with fellow amateur astronomers ended abruptly several years ago, when I accepted an invitation to travel across the Atlantic to join a small group high on a mountain. It was just a few short months after my late father passed away and I was still grieving for him. I was in two minds about going, as it was quite an expensive trip for me, but the organiser reassured me that I would be “closer to my father” on top of that high mountain, soaring 8,500 feet above sea level. Even though he knew I was a man of deep faith from our email exchanges, one evening he found occasion to taunt me in front of a few other guests, by claiming that there was no actual evidence that Jesus Christ ever existed! What a cruel, ignorant and insensitive thing to say! Rather than argue with him, I walked away and was immediately consoled by a fellow Christian in the group, who told me he had been fighting this kind of ignorance all his life. But we are to forgive our fellow men their trespasses and I have long forgiven him, though I hope that the same chap will more clearly understand that being a Christian is far from being a hairbrained, flash-in-the-pan way to think and live. It has, after all,  by far the greatest explanatory power that makes sense of the whys and wherefores of the world we find ourselves in.

As I explained earlier in this communication, I see no hard distinctions between glassing during the day and peering at the sky on a dark night. Afterall, the Earth is a planet too and it was created so that we could freely explore it! And though we live in a fallen world, where all of the creation groans for the fulfilment of the Lord’s promise to adopt the sons and daughters of Adam, we can still enjoy its beauty by studying the lifeforms that teem and multiply upon its surface.  And what better tool to explore this aspect of the physical Universe than with a good quality pocket binocular!

Here in the glen, mild days in late November invariably mean overcast, damp and often misty mornings and afternoons, with poor visibility. But thanks to the waterproof nature of my pocket glasses, I need never worry about them. A little rain on the optics and body armouring has no lasting consequences on the operation of such instruments. Indeed, I have come to regard their getting wet as a kind of initiation rite lol!

A little rain maketh the binocular.

Every denuded tree branch, every crawling insect, scurrying rodent, every fallen leaf, and grazing sheep upon the hillsides cry out for study with the pocket binocular. And because my field glasses possess excellent close focus capability, well under two metres, I can explore the dying days of 2019 in exquisite detail. But nature never ceases. She is in constant flux.

For the birds.

Gone are the green leaves of the deciduous trees and the warm sunshine they once basked in. Gone are the family of noisy magpies that rested in the Rowan tree in my back garden for much of the year. I still see them about and hear them chackering from afar off, but they have taken up residence elsewhere. And while the brambles have seen their halcyon days come and go, the brilliant white snowberries are ripe for the picking by hungry tree birds, as are the holly bushes now adorned with their brazen red fruits.

Exploring terrestrial astronomy.

What an extraordinary thing it is to be alive!

Doubtless, human knowledge has come a long way, with the mature sciences of physics and chemistry providing us with a wonderful platform to understand at least the salient features of the macrocosm and microcosm, between which we find ourselves. But though we have some measure of understanding of how matter behaves in the Cosmos, living things more and more, appear to be an exception. The more we study them, the more complex they are shown to be. Some men have deluded themselves into thinking that we understand the living state, but it is quite apparent that we are far from understanding what it really means to be alive. The growing things are a mystery and a law unto themselves! It is a curious thing that the Biblical Creator is uniquely known as the “Living God.” A Being who declares, “my glory I will not give to another”(Isaiah 42:8) When I contemplate the majesty and beauty of the living world, I can more clearly understand why the Living God would withhold His secrets from humanity, lest we destroy it, either in our ignorance or arrogance, or both. It’s one thing to have dominion over nature, to be responsible stewards of the biosphere, as it were, but quite another thing to play god. And though we continue to grope in the dark, I suspect that the essence of life may forever lie beyond the capabilities of science to elucidate.

Afterall, based on our track record, He has every right to withhold such knowledge from us!

A Stupendous Accumulation of Star Matter

The Andromeda Galaxy, as it appears on page 75 of our guide book.

The sky is rich in mystery.

Especially for the tyro.

I am reminded of a curious tale related by the Canadian-American astronomer, Simon Newewcomb(1835-1909), concerning a skipper who, having set out from England, while  plying the dangerous waters of the Atlantic Ocean, noticed a curious object in the crystal clear heavens, which he apparently sighted every night during his voyage. After docking in the New World, he eagerly made his way to the Observatory at Cambridge, Massachusetts, where he told the learned Professor Bond in no uncertain terms that he had discovered a comet! Bond was used to hearing such yarns however, and soon revealed to the gallant skipper that his ‘comet’ was, in fact, the great Nebula in Andromeda.

But the same object really is steeped in mystery. Afterall, its conspicuous, smudgy light must have been seen by humans far back into hallowed antiquity, yet there is nary a  mention of the ‘nebula’ by other great pre-telescopic observers, including Hipparchus and Tycho Brahe, nor even by the venerable Bayer. Indeed, the first tentative recording of it didn’t come until 974 AD, when the medieval Persian skygazer, Al Sufi, made vague reference to it, only to be re-discovered by the German astronomer, Simon Marius(1573-1624) on the long night of December 15 1612, when he examined it with a primitive Galilean telescope, describing it as a ” flame seen through horn.”

Spare a thought for poor ole Marrius. His ‘Dutch trunk’ had a field of view scarcely a quarter of an angular degree wide, so what he likely described was the bright nucleus and little more. The pocket binocular does immeasurably better however. The Andromeda ‘nebula’ is easily seen with the naked eye on a dark, moonless night from my back yard, presenting as a small, cloud-like smudge. And though it was always referred to as a nebula throughout much of the 18th and 19th centuries, it was finally shown to be a bona fide ‘Island Universe’ or ‘galaxy’  in the early 20th century, when its prodigious distance was finally estimated.

A pocket glass view of the great Andromeda Galaxy.

Through the pocket glass, its distinctve lenticular shape is easily discerned. The mid-section is brightest and represents the core of the galaxy, and extending off on either side of the core, your little glass ought to be able to allow you to trace its fainter spiral arms which extend its width to more than 3 angular degrees, or six full-Moon diameters. Messier 31, as it is also commonly known today,  has two smaller companons, analogous to the Large and Small Magellanic Clouds that orbit our own Milky Way; wee elliptical galaxies in their own right- M32, just south of the core and another, M110, situated a few degrees off to the north of the core. While both of these fainter companions are magnitude +8 or thereabouts, and so ought to be just visible with the pocket glass, I personally find them to be rather elusive in these pint-sized glasses.

Maybe you’ll fare better?

That said, it’s always an awe-inspiring sight to spy this distant galaxy in any optical instrument, however small. Most astronomers estimate that the Andromeda galaxy is as big, if not bigger than our own Milky Way, with somewhere between 100 and 400 billion stars. Its distance is worth contemplating also; between 2.2 and 2.5 million light years away.

The Scriptures inform:

But Jesus answered them, My Father has been working until now, and I have been working.

John 5:17

So, when you next cast your gaze on its ghostly magnificence, take a few moments to muse upon the perspective. When the light you see from it first set out across intergalactic space, our Creator was busy putting the final touches on making our jewel planet ready for the last Big Bang of His creation; the sudden introduction of human beings (Adam & Eve and their descendants), fashioned from the dirt of the ground(Genesis 2:7), uniquely made in God’s image, and freely able to think and wonder about the dark, wheeling vault above their heads!

Contentedness

For all that is in the world, the lust of the flesh, and the lust of the eyes, and the pride of life, is not of the Father, but is of the world.

1 John 2:16

The last Thursday of November is American Thanksgiving Day, where families across that great nation come together and give thanks to their Creator for the many blessings He has bestowed upon them. I wish we had something similar here, but the ugly head of  secularism makes that a very unlikely prospect. Unfortunately, we have had no trouble  adopting a less reverent American tradition, Black Friday, when some folk behave more  like animals, pushing and shoving their way into department stores in search of bling.

The hobby of astronomy is not immune to rampant materialism either. That’s one of the principal reasons why I turned my back on promoting vainglorious refractors, where I lusted after ever more expensive models just to feel like I had ‘arrived.’ I was just feeding a greedy habit. But then I took heir of myself and managed to break free from this vicious cycle, discovering the wonderful virtues of Newtonian telescopes, which have met all my needs as a keen visual telescopic observer; and saved me a great deal of money to boot;- funds to donate to more noble pursuits!

I didn’t need or want them any more. They have no power over me.

I have taken the same approach to pocket binoculars; I have chosen two models that offer all the performance I could possibly want. They’re not cheap, but neither are they overtly expensive.

I received a curious email a couple of weeks back from a chap who wondered why I didn’t go the whole distance and buy in the most expensive models, like the Swarovski CL or Zeiss Victory pocket, or some such. My reply was that I did not believe that I would be gaining anything in moving to a Swarovski, as the 8 x 25 model provides the same generous field of view(6.8 angular degrees) as my Zeiss Terra,  has the same light transmission(88 per cent), and though I have not field tested that particular model, I have very strong suspicions that the Zeiss is every bit as good– and may even be that little bit better – than the Swarovski CL pocket at half the retail price. And as for the Victory model; sure it offers a wider field of view in excess of 7 degrees and sports fluorite objectives. But my average eyes would very likely not notice any significant optical differences from the much more economical Terra(which also employs ED glass)  and I could happily live without that slightly wider field.

Don’t chase the wind.

So I don’t have any desire to have the ‘best.’ It’s an unhealthy attitude and a distraction from what’s really important. My instruments are well good enough for every application I employ them for. What’s more, even premium instruments develop faults.Take this report as an example. You’ll not likely hear anything like that on a public forum though, where their fanatics seem to be completely intolerant of any criticisms expressed about their ‘little babies’.

Happy with my chosen tools.

I am thrilled to bits with what I have.

I’m content; happy with my tools!

Surveying the Landscape

The view from the top of Dunmore, looking northeast over the Fintry Hills towards Stirling.  Black Friday morning, 2019.

Were it not for the tall conifers that lie in the common ground beyond my back garden, I would have an unobstructed view of Dunmore, a hill rising just over 900 feet above the valley floor. When our houses were first built in the late 1950s, there were no trees to block the view, as my wife reminds me when ever we look back over old family photos. Dunmore is just one of a number of gently rolling hills that comprise the Campsie Fells(Gaelic Monadh Chamaisidh) a chain of extinct volcanoes that date to the Carboniferous Period some 300 million years ago, when Scotland lay near the equator, and which stretch for about 16 miles from Denny Muir near Falkirk through Fintry and on as far as Dumgoyne in the west. Very popular among ramblers and hillwalkers, it also served as a convenient field site for geology undergraduates from Edinburgh and Glasgow Universities, who explore its many interesting geological features.

Columnar jointing in basalt sill under summit of Dunmore, Fintry, seen here in better light. Image credit: Edinburgh Geological Society.

After a short walk up an old winding dirt road, you’ll arrive at an abandoned red ochre quarry, an iron-rich, clay-like  mineral used as a pigment for paint in olden times, but more recently as a road sub-surfacing material.  From there, the path takes you over a couple of burns and some boggy ground until you reach the base of Dunmore. After a magnificent night of crystal-clear skies and freezing conditions, temperatures struggled to get above zero all day, and climbing even a small hill like this is not an inviting prospect for many who like their creature comforts. The low-lying Sun of mid-morning keeps much of the terrain in shade and one has to tread carefully on the icy surface underfoot, so you need to wrap up warm and wear appropriate boots with a solid grip. But as we approached the peak, the Sun had risen high enough in the sky to lend some of its gentle heat to us, and though it did not have much power, my wife and I were immensely grateful for its uplifting warmth which always raises the spirits.

The morning Sun illumining the Cairn atop Dunmore.

It only took 50 minutes from doorstep to summit and just 30 minutes for the descent.

We took along the lightweight Zeiss pocket to survey the sleepy valley below, still covered with a thin veneer of ground frost, but the visibility proved exceptional. Looking north, we could easily make out Loch Lomond about 17 miles in the distance, surrounded  by a string of Munros(mountains over 3,000 ft) of the Trossachs, the gateway to the Scottish Highlands. To prevent the fogging up of the ocular lenses, I kept the little Terra folded up in a warm pocket and enjoyed about ten minutes of intensive glassing, drinking up the magnificent quality of the morning light as I scanned the Fintry Hills across the valley and northwards towards our national park. The sumptuous late autumn colours were sublimely captured by the pocket glass, as were the chissled contours of the scraggy outcrops on the hills across the valley, bathed in a cobalt blue sky.

How great an artist is our Creator!

The view to the north, with Loch Lomond at centre left and the mountains of the Trossachs rising up into the sky.

It is no small wonder that the founding fathers of modern geology were Scotsmen; most especially James Hutton from the 18th century and Charles Lyell from the 19th  _ both of whom were surely provoked to reason by the stark and stunning beauty of the Scottish outdoors!

From such an elevated vantage one gets a clearer perspective on the sheer enormity of the landscape, its extraordinary age and our fleeting existence upon it. The Old Book says it far better than I can express it;

Man is like to vanity: his days are as a shadow that passeth away.

                                                                                                                          Psalm 144:4

It was well worth the effort to climb on this bitterly cold morning. But we had delicious homemade soup and a warm fire to greet us upon our arrival back home.

Orion Rising

The mighty constellation of Orion a few hours before meridian passage. Photo taken by the author on the night of November 29 2010.

December 1 saw the continuation of the cold snap. Temperatures once again struggled to get above zero all day, with nighttime lows of -6 or -7C, but the brilliant winter sunshine makes the cold much more bearable and even inviting. My Opticron Aspheric LE  8 x 25 with its excellent close focus of under 1.5 metres is a wonderful optical tool to explore the intricate architecture of ice crystals laid down by old Jack Frost in his relentless march across the countryside.

Leaves, flowers and tree branches are covered with delicate patterns and the grass beneath my feet takes on a ghostly silver glaze. I find that I have to reduce the interpupillary distance between the ocular lenses on the pocket glass to obtain the most compelling views on up-close subjects. Cold, cloudless nights with little in the way of wind engender the ideal conditions for the deposition of hoar frost. Hoar is a modern rendition of the old English words of ‘hor’ and ‘har’ meaning ‘grey’ or ‘white.’ Under such conditions, water vapour sublimates directly from the gaseous state in the air to solid ice without first condensing as liquid water.

Jack Frost has been busy creating a silvery landscape.

Because the low winter Sun casts its golden rays on the hills to the east of the village, it gets the lion’s share of their heat and so it’s not unusual to observe much more frost-free terrain higher up than in the valley below, creating lovely, stark binocular vignettes that I can enjoy simply by peering out my front livingroom window. Perhaps the most amazing effects of hoar frost occur when they envelope cobwebs and glass windows on greehouses and other such, which can create wondrous patterns that are as beautiful as they are fascinating to study.

Around 5pm, in deep twilight, a low lying crescent Moon hovered just above the hills to the south-southwest, beautifully silhoutted by the branches of a grand old Horsechestnut tree in the foreground. It was a delightful sight in the pocket glass, with its unilluminated side clearly seen bathed in earthshine. Some prominent craters were sharply defined all along the terminator, with no annoying glare or internal reflections that I have observed in lesser glasses.

On early December evenings, the constellation of Orion the Hunter arrives at a position of prominence only around midnight but doesn’t reach its highest elevation until it culminates in the south at around 1.30am local time. As a result,  I generally explore it with the pocket binocular late in the night, and sometimes on into the wee small hours. Our target this evening is the three prominent belt stars of the Hunter which can be studied from most any location, whether it be a brightly-lit town or dark country site. Our little guide book on pages 196 through 198 reveals their lovely appellations; from left to right, climbing ever higher are Alnitak, Alnilam and Mintaka. The excellent contrast of my pocket glass reveals the pure white colour of this curious stellar trio, which in itself betrays their young age in the scheme of things. The eye is naturally drawn to their almost perfect linear cast. Both Alnitak and Alnilam shine at the same magnitude (+1.7) but the lowermost Mintaka shines about half a magnitude fainter, though I find this somewhat surprising, as it always seems a little brighter than the guidebook suggests. Perhaps this is yet another splendid illusion caused by the equally brilliant stars towing the stellar line. What do you think?

Their similar brightness along the same line of sight also paints the distinct impression in the mind’s eye that they might be located at the same distance across the great dark of interstellar space. Actually, two of the belt stars are located at about the same distance from the solar system; Mintaka(700ly) and Alnitak(736ly). But you might be surprised to discover that Alnilam is situated nearly three times further away at over 2000 light years!

Placing the belt stars in the upper left of the binocular field, you’ll soon notice another white stellar jewel in the lower right of the same field. This is Eta Orionis; a dapper double star for the keen telescopist, resolvable into two components, and roughly aligned east-to-west in the high-power field of a small backyard telescope, under good seeing conditions.

As the belt stars climb ever higher as they approach the meridian, the pocket glass will enable you to bag progressively fainter members, arranged in curious loops and arcs around the brilliant three. However, because the belt stars never rise very high in my far northern latitude (56 degrees), the faintest members are better observed in larger binoculars. Indeed, the belt stars are but the brightest luminaries of a grander still binocular open cluster known as Collinder 70, comprising of some 100 stellar members down to the 10th magnitude of glory. Many of the fainter members are hopelessly beyond the power of my litte pockets to discern, but I have been genuinely thrilled by how many fainter suns that appear out of the sable depths, as the belt stars near culmination in the south. And if you’re lucky enough to live at more southerly latitudes, Collinder 70 ought to be an even more engaging sight in a humble pocket glass, as it will be placed higher in the sky. So, go out and have a gander!

The Sword Handle & the Magic Furnace

You don’t have to venture very far with the pocket binocular to arrive at our next port of call. Indeed, the little Zeiss Terra pocket glass can just frame the belt stars and the swordhandle, just south of the belt, in the same field! On a dark, moonless night, when the constellation approaches the meridian, the naked eye can easily detect three stars arranged more or less north to south. The middle ‘star,’ you will find, is most unusual, as it appears somewhat foggy, or out of focus. Placing the pocket glass to your eye will reveal a most interesting field, where the fuzzy star is clearly shown as a rather large cloud of incandescent gas, lit up from inside by young stars that were forged within the nebula relatively recently in the scheme of things; a few million years at the very most. This is great Nebula in Orion, or Messier 42, as it became known to stargazers. Indeed M42 is one of the nearest star-forming factories to our solar system, extending about 20 light years from edge to edge and some 1500 light years distant. In a medium sized telescope,  dark-adapted eyes will even reveal that it’s not white but actually glows in a kind of surreal, ‘protoplasmic’  green, but try as I may, the small objective lenses on the pocket glass have not revealed any colour beyond a dull, white or grey. A small telescope at higher powers will show you a neat quartet of stars- known famously as the Trapezium – at the heart of the nebula.

The Swordhandle of Orion as observed in the pocket glass. For more details see page 199 of the guide book.

To the north of M42, the magic furnace, my eyes can just make out a pair of smudgy stars known prosaically as NGC 1977, by employing a clever little trick called averted vision i.e. by turning your eye a little to the side to best utilise the most light sensitive part of your superbly designed retina. Their slight smudginess is due to a thin veil of interstellar gas out of which these suns were originally forged. And just above these lies a pretty configuration of about half a dozen stars making up the loose star cluster, NGC 1981. Intriguingly, nearly all of the cosmic real estate you’re looking at – including the stars and the whispy nebulosity – is located within a neat little bubble of interstellar space roughly 300 light years in diameter and between 1200 to 1500 light years distant.

Together with the Sun and many other stars taking up residence in the solar neighbourhood, the effulgent jewels of Orion inhabit but a minor tributary of the Milky Way galaxy, known as the Orion Spur. But we can thank our Creator for settling our world here, well out into galactic suburbia, where it laps the centre of our galaxy in a near-circular orbit, taking nearly a quarter-billion-years to do so. Here, the Sun and its magnificent retinue of planets, enjoy much darker skies than the vast majority of other locales within the galaxy, a place where humanity can fully explore the vast cosmos in which he finds himself in – a platform for vigorous exploration if you like – and safely tucked away between two major spiral arms. This highly strategic locus helps keep our world at a reassuringly safe distance from their deadly gravitational tug, which would otherwise have scuppered the progress of life on Earth in general, and human beings in particular.

You see, we have so very much to be thankful for!

King David of old knew it all too well:

The heavens declare the glory of God; and the firmament sheweth his handywork.

Day unto day uttereth speech, and night unto night sheweth knowledge.

There is no speech nor language, where their voice is not heard.

Their line is gone out through all the earth, and their words to the end of the world.

Psalm 19:1-4

 

Be sure to pay a visit to the Swordhandle of Orion whenever you’re next outside on a clear, December night. Who knows? The heavens may well shout out to you!

What do you hear?

Pocket Binoculars: Why the Relative Expense?

It occurred to me that even though I’m the happy owner and user of larger binoculars, good pocket glasses are really quite expensive. I mean, my most used general purpose binocular, a Barr & Stroud 8 x 42 Savannah(a very fine optic!) retails for about the same price as my little Opticron Aspheric LE, and the Zeiss Terra pocket glass retails for about twice as much again! Nor is this peculiar to my particular purchasing choices. Indeed, you can find many examples of high-quality pocket glasses that retail for higher prices than many excellent full-size binos. Furthermore, in terms of optical performance, these pocket glasses are without question inferior to any decent full-size instrument, particularly when glassing in low light conditions, such as at dusk and dawn, or when observing the night sky. So what’s going on here?

It’s a legitimate question, and it took me a while to stumble on the answers. While a full-sized bino is unquestionably more immersive and useful under a wider range of observing conditions, they are far less portable than their pocket-sized brethern. Simply put, you can’t stick them in a pocket and get going in the same way you can with tiny, elegant pocket glasses. But I believe there is a still more fundamental reason why quality pocket binoculars command the relatively high prices they do.

Roof prism binoculars are amongst the most complex optical accoutrements employed by nature lovers, and as the technology is scaled down, it becomes more difficult to assemble such intricate devices – with their smaller Schmidt-Pechan or Abbe-Konig prisms, lenses and more diminutive housings needed to hold the optical system rigidly in place. Simply put, ornate little glasses like these take real skill in their proper assembly, with commensurately tighter mechano-optical tolerances compared with larger glasses. Thus, seen in this light, it’s not really surprising that such elegant optical devices as these command the relatively high retail prices they do. They’re just harder to manufacture than larger glasses.

Small, precision optics require more effort to make well.

So, not such a great mystery afterall!

Moongazing

A full Moon in a cloudy sky can create dramatic light shows.

And God said, Let there be lights in the firmament of the heaven to divide the day from the night; and let them be for signs, and for seasons, and for days, and years:

And let them be for lights in the firmament of the heaven to give light upon the earth: and it was so.

And God made two great lights; the greater light to rule the day, and the lesser light to rule the night: he made the stars also.

And God set them in the firmament of the heaven to give light upon the earth,

And to rule over the day and over the night, and to divide the light from the darkness: and God saw that it was good.

Genesis 1:14-18

As Holy Writ informs us, the Sun was given to rule over the day and the Moon and the stars to light our way at night. They exist to allow us to tell the time and the passage of the seasons. But the Almighty also arranged for humankind to be placed on this planet in a unique window of time where perfect solar eclipses are possible. By an amazing coincidence(I’d say miracle), the Moon is 400 times smaller than the Sun but the Sun is 400 times further away than the Moon. As a result, we can experience the majesty of a total solar eclipse and gain some measure of His supernatural creative power.

Many amateur astronomers consider the bright light of a full Moon to be little more than a natural source of light pollution, where much of the grandeur of the starry heaven is drowned out by its intense, silvery light. I too considered the full Moon to be more of a nuisance than anything else, but when I re-discovered the simple pleasures of binoculars, my enthusiam for observing the full Moon received a new lease of life.

That said, it is not so much the sight of the full Moon on a clear December night that piques my attention, so much as the spectacular light shows Luna stages for us when its reflected sunlight interacts with the water-laden clouds coursing above my head. Water acts like a weak prism, refracting and dispersing moonlight, painting beautiful colour portraits on the canvas of the sky.

I ventured out into my back garden shortly after 1am on the morning of December 11 2019 to observe a nearly full Moon, now a little past meridian passage, and beginning to peek through the thick rain clouds that had soaked the land all day, and on into the late evening. I knew that this would create the ideal conditions for the Moon to do its colourful magic, so I ran inside and fetched by little pocket glass and turned it on the bright Moon as the clouds rushed past it from the west. I was rewarded with a magnificent display of light and colour, with the clouds soaked in various shades of red, pink, orange and yellow. The most intense colours occur when the clouds are closest to the Moon and gradually fade as they venture off to the east. Every now and then, a series of small but especially dense clouds create an eerie blackness in the binocular portal, like spilt ink upon cured vellum. No two moments are ever alike, and each view through the pocket glass shows unique combinations of light, colour and shade. The clouds too reveal gloriously complex and beautiful expressions of form; mesmerizing sheets, ripples, and all manner of curiously shaped wisps.

Such dazzling displays of light and form speak volumes concerning the creative power of the Lord of Light, in whom there is no darkness to be found.

Alas, this godless generation readily worships the creation but not the Creator.They refuse to acknowledge the artist but will readily enjoy His handiwork. The cult of Earth worship aims to create a spirit of fear within man’s soul. But fear is of the evil one and not of God.

If only they knew the firm promises of the Lord of heaven’s armies:

While the earth remaineth, seedtime and harvest, and cold and heat, and summer and winter, and day and night shall not cease.

Genesis 8:22

Which part of this do they not understand?

The Kaleidoscopic Star

The Jewel of Canis Major: Sirius.

While we’re on the subject of colourful light shows, here’s yet another one to explore with your pocket binocular. Mid-December is a fantastic time to get to know the brightest star in the firmament; Sirius, the Dog Star. It’s easy to find by following the diagonal line of stars downward from Orion’s belt until your eye meets with its intensely brilliant light. Sirius is fascinating to watch with the naked eye and with the pocket binocular, as it coruscates wildly: one moment it’s white and then the next it flashes green or blue or even red; indeed, all the colours of the rainbow! The phenomenon is especially thrilling at my far northerly location, as Sirius never rises very high in the sky, even when it culminates in the south, but that significantly enhances Sirius’s kaleidoscope-like antics as the star passes through very dense air near the horizon.

The pocket glass greatly enhances the view owing to its greater light gathering power over the human eye. Because Sirius lies very far away in space, its light acts like a point source, passing though air cells of varying temperatures on its way to your eyes. As a result, its beams get refracted and dispersed at slightly different angles which gives rise to its frantic twinkling. It’s a well and truly heart-warming sight to behold on a cold winter night.

Sirius shines so brightly not because it’s an especially big star – it’s only twice the mass of our Sun and 25 times more luminous. Its great apparent brightness is mainly due to its close proximity to the solar system – just 8.6 light years in fact. Were Sirius to replace the Sun in our skies it would be 70 per cent larger than the solar disk and daylight would be painfully bright. We’d all have to wear ultra-dark sunglasses even on an overcast day until it sunk below the horizon. And don’t forget to wear factor 200 sunblock to protect you from its ferocious ultraviolet flux. No, if the Sun were replaced by Sirius it would be game over for all terrestrial life on Earth. We can thank our Creator for not subjecting us to its lethal rays.

Sirius has a neat little secret quite beyond the capabilities of your pocket glass to discern. Tucked up very close to it lies its curious companion – Sirius B – the nearest white dwarf to the solar system. With a size only about one per cent of our Sun, a teaspoonful of its exotic matter would weigh more than a fully grown elephant! Siriius B completes one orbit of its primary every half century.

If you place Sirius toward the top of the binocular field, and glance at the bottom of the same field, your little glass will pick up a pretty cluster of stars known as M41, spread across an area of sky about as large as the full Moon. Our guidebook on page 100 informs us that it contains about 80 stellar members but only the brightest dozen or so are picked up in the pocket glass. Those who live at more southerly latitudes will fare better with this cluster under a good, dark sky, as its altitude above the horizon will be greater.

Asymmetrical Optics:

Comparing small glasses: Zeiss Terra 8 x 25(top) and Celestron Trailseeker 8 x 32(bottom)

On Sunday evening, December 15 2019, I fetched all of our Christmas bling from the attic and began decorating the house with tinsel. After that, the small Christmas tree went up wiith still more tinsel and baubles and fairy lights.

After midnight, I stuck my head out the front door to be greeted by a bright waning gibbous Moon already high in the east. I fetched my little Zeiss Terra pocket and aimed it at its silvery surface. It was a fine sight with plenty of crater detail re-emerging after full Moon earlier this week. I moved the glass first left and then right laterally across the field, examining how crisp the image maintained itself as I moved the Moon off axis. Then I remembered something I had experienced in my larger 8 x 42 glass many Moons ago lol, so I re-centred Luna but this time moved it up and down, to the top and bottom of the field, respectively. There it was again! The image remained well defined at the edges of the field when moved from left to right but was noticeably softer when I examined the lunar image at the top and the bottom of the field!

Hmmm

Next, I ran inside and grabbed my 8 x 32 Celestron Trailseeker binocular to see if it would do the same thing; yesiree, I got the same result with that glass. So, out came my little Opticron LE Aspheric 8 x 25, my Barr & Stroud 8 x 42 and my 10 x 50 big guns, proceeding again with the same tests. And what do you know? I got exactly the same results with all these glasses too!

My mind was set racing and then I recalled an online review on a birding forum, where the poster was describing his impressions of his new 8 x 30 Swarovski CL Companion; and there too the gentleman reported the same result: softer top and bottom-edge images compared with right to left impressions!

Pepperidge farm remembers!

Dinnae get yer tinsel in a tangle,” I jested to myself.

I deduced that this must be a universal property of Schmidt-Pechan roof prisms. How curious a result!!

No binocular image is perfect!

Ordinary Things We Take for Granted:

The holly bushes are ready for pruning.

Here we are a week before Christmas.Daylight has become dreadfully short. On an overcast afternoon this far into the year, you might as well pull your curtains and call it a day at 2pm! Colourful things are hard to come by. But I know where to go find some. Bleeding their intense colour into the leaden air, the holly bushes near my home are ripe for the harvest. And the colour of dusky skies never cease to impress.

The light always overcomes the darkness.

Isn’t it a wonderful thing to be able to see!

Anything!

To be granted the power to explore the world around us. It is one thing to be able to see your immediate environment, but quite another to see the distant stars and the galaxies beyond. As a scientist who has rejected scientism, I’m free to ponder questions that go well beyond the ken of some of my peers, who have boxed themselves in by embracing a kind of dead-end philosophy roughly described as Humean materialism. I can ask questions only a child would ask. Why can we see the stars? Why can my pocket glass show me crisp views of a last quarter Moon rising late in the east? Lots of questions; why questions.

If we lived on a planet with thinner air, we’d be able to see the stars a little more brightly alright, and more steadily for sure. But at what price? Well, they wouldn’t sparkle as much,  and we’d likely freeze to death!  If we monkey around with the pressure of the air too much, our lungs couldn’t work well and our senses would be dulled. Seeing anything would be painful.  If the air pressure were trebled or reduced to just one third of that which we experience at sea level, we’d have reached the limits of their design. But even here some intriguing results emerge from the murk.

A Creator who has granted humanity the freedom to explore might have designed the elevation of the highest mountains to coincide with the physiological limits He imposed on his human imagers. Curiously, geophysicists have worked out a simple formula showing how the Earth’s atmospheric pressure varies with altitude;

P(h) =Poe^-0.14h

Where P(h) = pressure at any height  h (in km)), Po= the air pressure at sea level.

So P(h)/Po = e^-0.14h

Thus ln(P(h)/Po) = -0.14h

from which we arrive at h = ln(Po/Po)/-0.14

Now let’s crunch the numbers: physiologists inform us that the lowest pressure, P(h), healthy humans lungs can work at is about 0.33 atmospheres. Po we set to 1.0,  to obtain:

h =ln(0.33/1)/-0.14 = 8km!

Isn’t that interesting! It turns out that the Earth’s highest mountains(Everest is 8.8 km) are about the same size!

But what about seeing the stars? Well it turns out that the intensity of a light beam through the atmosphere of opacity k (its ability to pass light through itself) also obeys a similar law;

I(x) = Ioe^-kpx

where I(x) = the intensity of a light beam at a distance x,  Io = the intensity at x = 0, and p = the mass density of the atmosphere.

By  fiddling with the numbers, we can amuse ourselves on a cloudy night. For example,  if we were only to double the mass density of our own atmosphere, keeping everything else the same, the light from the stars would be diminshed by nearly an order of magnitude; as through a very dark glass, dimly. And what if we were placed on a larger world with a commensurately larger atmospheric column, the attenuation of starlight would follow the same rules.

Would we be able to see the stars at all?

The mind boggles!

Away in a Manger

The Beehive in Cancer as depicted on page 97 of our guide book.

The winter solstice has finally arrived. Slowly, Sol will regain its strength by tracking back northwards, climbing ever higher in the sky as it does, towards the vernal equinox and onwards to the summer solstice.

Our next target, located in the constellation of Cancer, the Crab, has a decidedly Christmas theme. But you’ll have the stay up late to get a good view of it this early in the season. Known as Praesepe, the Beehive cluster(M44), or the celestial Manger. It’s fairly easy to locate as a misty spot about three Moon diameters in size, down and a little to the left of the twins, Castor and Pollux.  On a dark night with good transparency, a pair of naked eye stars, Gamma(magnitude +4.7) and Delta(magnitude +3.9) Cancri, are seen flanking Praesepe on its eastern side. In earlier times, these were better known as Asellus Borealis(Gamma)- the southern ass – and Asellus Australis(Delta) representing its southerly counterpart. I suppose these Latinised names hearken back all the way to Roman times, when these ancient sky gazers naturally saw them as little donkeys about to tuck into tasty morsel of hay(denoted here as the Beehive).

The pocket binocular transforms the view, revealing a vivacious cluster of faint stars, very much resembling a swarm of busy bees, set in the midst of an interesting trapezium of brighter suns. In the binocular portal, the Aselli constitute the two brightest luminaries of the trapezium seen on the left-hand side of the field.

 I have spent a few late night vigils comparing the views of the Beehive in my Opticron Aspheric and Zeiss Terra, and while the Terra gives a wider field of view, the little Opticron frames the entire asterism – the Beehive and the Trapezium – that little bit better, owing to its smaller field of view. Moreover, I have not been able to convince myself that the slightly brighter daylight images served up by the Terra reveal any fainter stars in the Beehive than with the Opticron.

The Opticron pocket glass frames some celestial real esate better than the Zeiss.

Located about 590 light years from the solar system, my average eyes can make out about a dozen or so distinct stars within the Beehive with the pocket glasses. But that’s the case when it’s still a couple of hours from meridian passage in the south. Though there are several dozen fainter members in this visually stunning open cluster, the best the pocket glass can reveal of them is a rather diffused ‘nebulosity’, which imparts a somewhat ghostly cast to this communion of suns. Later in the season, when Cancer is better placed nearer the meridian at a more respectable hour of the night, I will likely ferret out still fainter members.

Praesepe as it appeared in the pocket glass at 1.20 am on the morning of December 18 2019.

Praesepe is a most beguiling sight in larger binoculars or a small, rich-field telescope. It is all the more thrilling to visit this comely little patch of sky on the lead up to Christmas, when we commemorate God’s momentous decision to send his only begotten Son into His own creation in order to redeem His fallen imagers – humankind.

As the Scriptures proclaim:

In the beginning was the Word, and the Word was with God, and the Word was God.

 

The same was in the beginning with God.

 

All things were made by him; and without him was not any thing made that was made.

 

In him was life; and the life was the light of men.

 

And the light shineth in darkness; and the darkness comprehended it not.

                                                                                                                                John 1:1-5

Storage and Maintenance

The gentleman who kindly provided a review of the Zeiss Terra and its performance in comparison to the Swarovski CL pocket binocular later stated in another thread that the Terra cannot fit inside its clamshell case without turning down the eyecups. But I have found that this is simply not so. As you can see from the following sequence of images, it most certainly can! And not only that; many reviewers have claimed that the binocular cannot fit inside its case with the strap attached. But I found a very simple solution; by wrapping the strap ’round the eyecups and the bridge as shown in the images presented below.

The folded Terra with its eyecups fully extended in comparison to the dimensions of the carry case.

The neck strap can be wound around the eyecups first and then around the bridge as shown.

The binocular with its eyecups fully extended and with the straps tightly wound around the binocular, fits snugly in the case.

Protect your investment with silica gel sachets.

The binocular snugly stored inside the clamshell.

Having the eyecups permanently in the extended position serves two useful functions. Firstly, it speeds up the length of time it takes to get the instrument up and running. Simply unfold the binocular to your correct IPD and you’re in business. Secondly, it reduces mechanical wear and so ought to significantly extend the lifetime of the eyecups. This is especially the case since it is the eyecups that are normally the first thing to malfunction on any binocular after prolonged field use.

Because moisture is the sworn enemy of all optical instruments, I store all of my binoculars in a cool pantry at about 60F with a sachet of silica gel.

I try to avoid cleaning the optics as much as possible, as the delicately applied coatings on the optics are fragile and can be damaged either by overly aggressive rubbing or cleaning them too frequently, or both. When significant amounts of grime build up on the optical surfaces, I usually start by taking a good quality lens brush to remove any loose dust or particulates on the glass. After that, I use the supplied lens cloth soaked in a little Baader Optical Wonder fluid and apply it gently but firmly to the lenses, removing any remaining grime in a single, circular stroke.

Bird & Squirrel Watching

Pocket binoculars are supremely useful in a big city.

With winter now truly upon us in the closing days of December, the birds find it more difficult to acquire food. That’s why I always put some extra seed in the bird feeder, but even then, they seem more plaintive than usual. I’ve been spending time learning how to spot and identify more bird species in the numerous copses near my home. Just recently I learned to identify Treecreepers with their speckled mantles and long, distinctively curved beaks. Sometimes I’m lucky enough to see one climbing up the branches of the Rowan tree in my back garden, but more often, I see them on my walks along the riverbank. Just a few days ago, my wife alerted me to the presence of a pair of Wrens in the garden, sounding out a very distinctive ‘tic tic tic‘ as they hopped from one branch to another. Wrens; such tiny and perfectly formed creatures!

While visiting my in-laws in the west end of Glasgow over the festive period, I took along my little Opticron Aspheric for the ride. My sister-in-law is a keen birder with many years of experience and always keeps a small binocular on her window ledge overlooking the communal garden at the back of their home. And it was here that I sighted a beautiful Waxwing for the very first time! It has a very distinctive crest, with black, white and red wings, and a lovely-ruddy brown belly. Such a handsome bird to glass! My RSPB quidebook informed me that these birds do not breed in the British Isles but migrate here from Scandinavia over the winter in search of better food sources and milder climes.

.And if the birds don’t show up, there’s always the acrobatics of Grey Squirrels to admire as they scurry about on walls, trees and even the odd telephone pole right next to a railway line! That said, I have yet to see a single Red Squirrel in the city. But I have sighted the odd one in the trees along the road up to Culcreuch Castle near my home. It’s nice to see they are still with us in the midst of the more adaptable (and common) grey species.

A Red Squirrel scampering about in a conifer tree in the grounds of Culcreuch Castle.

 

The Blessings of a Clear Sky

A beautiful crescent Moon culminating in the south at dusk on New Year’s Eve.

One of my favourite times to be outside is at dusk- that magical episode between daylight and darkness. It is often a peaceful and contemplative time, where I can more deeply ponder the wonders of creation. With no wind, a hard frost and a crystal clear sky, the only sound that is discernible is the flow of water along the shallower streches of the nearby River Endrick about a hundred yards away as the crow flies.

A beautiful waning crescent Moon hovers above the denuded horsechestnuts and my pocket glass provides a wonderful portal to behold its magnificence with its well defined craters starkly on display along the day-night terminator. I never tire of seeing this celestial wonder. The sense of awe it upwells within me is in many ways indistinguishable from an act of prayer. As the Sun continues its journey below the southwestern horizon, the colour of the sky transforms from a deep blue to a purple or pink colour, which slowly fades as true darkness wraps her cloak around the landscape.

In the east, the wonders of Taurus are already well placed for observation; the visually magnetic Pleiades and Hyades, followed fast on its heels by Orion and Gemini. With full darkness, I marvel at the beauty of the bright stars already shining prominently in the early evening; creamy Capella, ruddy Aldebaran and Betelgeuse, and low down in the west and northwest, the bright summer luminaries, Altair, Deneb and Vega shine with a soft white hue.

High overhead lie Perseus and Cassiopieia, which are always a visual treat in the tiny pocket glass, with their teeming multitudes of bright stars. Our next target lies about mid-way between the main stars of these constellations; the pictureque Double Cluster – but it’s best to wait until the Moon has set before seeing them well in the pocket glass.

The location of the Double Cluster, featured on page 206 of our guide book.

The Double Cluster (also known as Chi Persei) is easy to find this time of year, as it rides very high in the sky. Look for a smudgy patch of light about mid-way between the ‘wonky W‘ of Cassiopeia and Perseus, the Celestial Hero. Most any optical device will show an improvement over the naked eye view. My pocket glass reveals a very rich stellar milieu centred on both clusters, with only the brightest stars being distinctly resolved in the small aperture of these instruments. Like the Beehive Cluster discussed earlier, the faintest members of each cluster remain umresolved, only presenting as a generalised fog to my average eyes. Still, the Double Cluster lies in a very rich part of the sky, with the great river of stars we know collectively as the Milky Way meandering right through both constellations.

The Double Cluster is often the very first object I observe when using binoculars or a telescope, the view becoming ever more magnificent the greater the aperture employed. Both clusters lie about 8,000 light years, according to our guidebook and are quite young as open clusters come – approximately just a few million years old. Curiously, astronomers believe that a significant amount of interstellar dust lies between us and these clusters, which extinguishes much of their true majesty. Still they remain one of the most arresting sights in all of the northern heavens. Finding the sky partially clear late on New Year’s Day 2020, I made a simple sketch of these clusters and their interesting hinterland for reference. Once you’ve examined the Double Cluster with your pocket glass, it pays to re-examine it with a larger instrument to get even more spectacular views.

The Double Cluster, as it appeared in the pocket glass at around 11.45pm on New Year’s Day 2020.

Alone with a January Full Moon

Truth be told, I ascribe little significance to the coming of a New Year. While many people make New Year’s resolutions, promising to change their ways or do something better and more positive in their lives, more often than not, they soon revert to their former state. Why, praytell, does the arrival of a New Year serve as a catalyst for change? The God I love and serve promises to renew us each day, every day, if we let Him be in the driving seat of our lives. As the prophet Jeremiah wrote some 26 centuries ago:

It is of the Lord‘s mercies that we are not consumed, because his compassions fail not.

They are new every morning: great is thy faithfulness.

Lamentations 3:22-23

After a day of torrential rain and high winds, the evening of January 11 2020 proved memorable. An immaculately pure Moon rose early in the east, and as the low-altitude rain clouds moved off into the North Sea, they left behind a vast array of smaller, fluffy cirrocumulus clouds, creating a beautiful, ‘mackerel sky’. Such cloud formations are commonly observed here during  the more settled, cold weather of winter. Illumined by its marble-white rays, this glorious meteorological spectacle was an arresting sight in my pocket binocular.

The Moon is our loyal companion in space. It’s always there, steadfast and dependable. Our Creator not only fashioned the Moon so that we might wonder at its beauty. Its penetrating, steely light shines through the darkness, reminding us that our God is with us, through thick and thin.

Over the long ages in the history of our world, the Moon played an indispensable role in keeping Earth habitable.  Were it not so large and so close, global weather systems would long ago have ceased to keep our climate mild enough to support such an enormous diversity of living things that help maintain the lives of billions of human beings, each one of us fashioned in God’s image.

I am constantly struck by the intensity of the whiteness seen across vast swathes of the lunar surface at full Moon. I can think of no other sight that presents such extreme whiteness. The brave Apollo astronuats who sojourned to the Moon during the late 1960s and early 1970s revealed to us a world almost completely devoid of colour; just a vast desert of bleached rock and sand enveloped by an airless, coal-black sky. In comparison with even the dullest winter day on Earth, our Moon is almost devoid of colour. Perhaps it was this great abandon of chromaticity that prompted astronaut, Michael Collins, to pen these haunting words as he gazed down in loneliness from his lofty vantage 75 miles above the new world from lunar orbit back in July 1969, hoping and praying that his colleagues would make a successful landing:

I am alone now, truly alone, and absolutely isolated from any known life. I am it. If a count were taken, the score would be three billion plus two over on the other side of the Moon, and one plus God knows what on this side.

Collins spoke the truth; no one is ever truly alone. Our God, who holds all things together (Colossians 1), is always with us!

Betelgeuse Fading

By mid-January Orion the Hunter reaches the meridian before midnight, and so is much better placed for those who must rise early. But there is something most peculiar going on with its brightest star; Betelgeuse. Take another look at the photo I made of Orion back at the end of November 2010;

The mighty constellation of Orion a few hours before meridian passage. Photo taken by the author on the night of November 29 2010.

Betelgeuse is the bright red star at the top left of the constellation, while Rigel is seen shining with an intensely white hue at the bottom right of the image. The image shows that Betelgeuse is slightly brighter than Rigel, but if you go and compare both stars now, you’ll see that Rigel is actually brighter than Betelgeuse! Indeed, since October 2019, Betelegeuse has faded back from being the 10th brightest star in the heavens to now being the 21st brightest star!

The pocket glass allows you to see the colours of both stars more easily but it will also show you that Betelgeuse is a lot fainter than it was even a year ago. What’s causing this? Well, Betelgeuse is a red super-giant star that is approaching the end of its life. Unlike smaller stars like the Sun, which is fated to die as a planetary nebula, where its outer atmosphere is expelled to the cold, dark of interstellar space, Betelgeuse is destined to end its life as a spectacular supernova explosion. At its distance of 640 light years, we need not fret, as it is a safe enough distance from us. That said, it will become brighter than the full Moon and will transform the night sky on Earth for many months or even years. The best estimates made by expert stellar astronomers suggest that Betelgeuse will go Kaboom sometime in the next 100,000 years, but that means it could explode tomorrow, next year or far in the future. We simply don’t know when exactly.

Still, it is thrilling to monitor this star in the winter night sky knowing that it could be all over for it within my own lifetime. What an amazing prospect!

Two Ruby Suns & an Open Cluster in Gemini

A visit to the northern foot of Gemini.

The winter night sky has an energy all of its own. Like time and tide, it waits for no one. And though January is usually the coldest month of winter, it is also one of the best times to observe the splendour of the heavens, especially when the Moon is out of the sky. And what a magnificent procession of celestial treasure to admire with a pocket binocular! By 10 pm local time in the third week of January, mighty Orion has reached the meridian, with Gemini following fast on its heels to its east. The wonders of Taurus –  the Pleiads and Hyads –  have by now fallen lower into the western sky, sparkling over the conifer trees to the west of my house. Mighty Auriga, the Charioteer, looms high in the sky and casting my gaze northwards, both Perseus and Cassiopeia are still very well placed for observation. Beyond Gemini to the east, Cancer and Leo are beginning to assert themselves, while the Plough dominates the sky to the northeast, with the stars comprising the handle of the Ploughshare curving their way toward the eastern horizon, marking the spot where the bright spring star, Arcturus, will rise in the wee small hours of the morning.

Our next target lies at the northernmost foot of the celestial twins, indicated on page 153 of our guidebook. The pocket binocular reveals a very pretty field of view, featuring not one, but two red giant stars with a prominent ghostly patch of luminous matter about the size of the full Moon, just off to the northwest of the binocular field.  The eastern-most star is Mu Geminorum, which shines with a soft orange hue at the third magnitude of glory. Because it lies so close to the ecliptic – that narrow path followed by the Sun throughout the year – it is often occulted by the Moon and (less frequently) the brighter planets.  A little further west of Mu lies Eta Geminorum, or Propus, which shines with roughly the same brilliance. Both stars are of late spectral type M, so they are considerably cooler and more highly evolved than our Sun. Those interested in double star astronomy will find Propus to be a real challenge. Telescopes with apertures of 4 inches and above, under good seeing conditions and very high magnifications, can tease apart its very close-in companion. But it’s a lot easier said than done! The variability of such M-class giant stars means that can flare up from time to time making close companions much more difficult to prize apart.

That moon-sized foggy patch to the northwest of these ruddy stars is M35, one of the most celebrated open clusters in the northern heavens, and a wonderful sight in a small rich-field telescope at low to medium magnifications. Though far beyond the abilities of the pocket glass to resolve, M35 consists of about 200 stellar members and lies about 3,000 light years away. If you have a few minutes free to venture out of doors, now is a good time to observe this most bountiful patch of the cosmic creation.

A Surprise at Sunset

Fintry Kirk, Scotland.

I rise early every Sunday morning to walk the mile journey from my home to my local Kirk, to pay homage to my Creator and Redeemer. I enjoy the stroll, as I get a chance to gather my thoughts and contemplate the beauty of the surrounding hills, especially when the weak rays of morning sunshine illumine their summits. January 19 was a clear and frosty morning, with ice under foot, but the few clouds to the east were dappled in radiant pink hues that slowly lost their beautiful colour as the Sun rose higher in the eastern sky. The remainder of the morning was bright and sunny but as AM gave way to PM, more cloud moved in, which subdued the natural colours of my surroundings somewhat, but at least it lifted the temperature of the air.

I took off for another walk with my eldest son in the late afternoon, enjoying the dry conditions and the extra hour or so of daylight as our world hurtles northwards from the winter solstice towards the vernal equinox. As always, I carried my pocket glass to enjoy the beautiful light on the landscape as the Sun made its way towards the southwestern horizon. We stopped at Culcreuch Pond, a favourite observing place, where I like to watch aquatic birds, mostly Mallard ducks, noisy ‘kowking’ Coots, and if I’m lucky, a sighting of the more common raptors that eke out a living here, especially Buzzards,  which are often seen patrolling the skies above the farmsteads around the village, and which make their nests in the lofty crags high above the valley floor. Today my son and I were greeted by a new visitor, a Grey Herron, standing motionless in the reedy shallows, with an outstretched neck and brazen yellow beak, staring at the water below it, hoping to catch some supper. Located about 80 yards away as the crow flies, the 8x pocket glass proved ideal for getting the perfect image scale to see this beautiful, big bird hunt. Sharing a look through the glass, we were both amazed how still the Herron fixed itself in pursuit of its prey.

I was hopeful that I would also gain a glimpse of a planet that is now beginning to grace the evening sky – majestic Venus, the celebrated morning and evening star. Alas, the clouds decorating the skies above our western horizon beyond the pond made any such sighting well-nigh impossible on this occasion, but nature has a genius for creating surprises. And that surprise came just before sunset, when the sky took on a most wonderful fiery cast, reflected in the still waters of Culcreuch pond, and beautifully silhouetted by the sleepy deciduous trees arrayed along its banks.

Sunset on the evening of Sunday, January 19 2020. Looking west over Culcreuch Pond, Fintry.

When we finally arrived back home, we were inundated with a plethora of beautiful pictures of red and golden sunsets snapped by our neighbours and friends right across the country, who also took some time out to enjoy the extraordinary light show of a Scottish sunset. Irrespective of creed, colour or culture, humans have a predilection for seeking out natural beauty; a gift bestowed upon us by our mighty God, the Author and Finisher of all things winsome:

Thou art worthy, O Lord, to receive glory and honour and power: for thou hast created all things, and for thy pleasure they are and were created.

Revelation: 4:11

Watching Nature and the Heavens Change

Snowdrops by the river bank.

January 2020 has been rather mild as Scottish winters go; nary a sign of snow in the lowlands just yet, but things can change rather rapidly, as previous winters have proven so abundantly. I’ve made the most of the dry and mild conditions though, as well as the lengthening days, to get out and about during my free time. Bundles of snowdrops have now popped up all along the banks of the Endrick River, a good sign that the progress of the seasons is unravelling apace. But it will be a while yet before the yellow Daffodils grace the valley with their radiant beauty.  The most dramatic colours offered by nature are still dominated by the green lichens and mosses that flourish all over the tree trunks. My pocket glasses reveal these natural wonders in astonishing clarity, filling the binocular field with riotous shades of lorne, contrasted against the grainy greys and tans of tree bark. Even on dull days, these colours are dramatic and ubiquitous, lifting both the mind and the senses.

I’ve been scanning the banks of the river for signs of more life and recently I observed a tiny little Wren drinking water at the river edge before retreating into a hole under the muddy banks. At first it seemed perturbed by my presence directly opposite it, on the other side of the river, scuttling inside the hollow for shelter, but by lying low and keeping still, it didn’t remain shy for long, poking its head out and re-emerging into the daylight. Since that afternoon, I have watched the same spot on the riverbank with my pocket glass to see if the bird had any lasting association with the place; and sure enough, I have now seen it  here a couple of times since. Maybe it’s thinking of making a nest there? Consulting my RSPB guidebook on birds, I learned that Wrens produce their young in April, so maybe my observations are a little premature. Time will tell.

In the heaven above, I’ve also been watching the fascinating fall from grace of Betelegeuse, where it continues to fade in glory and now only rivals the belt stars in general brilliance. The internet is awash with speculation about what’s going on. Some say it will go supernova, while others think it may actually collapse out of existence as a black hole. But all I know for sure is that Orion looks different now; it’s just not the same. Maybe a sign of something else? Afterall, our Lord did tell us to watch for signs in the heavens and on Earth.

And I continue to watch.

A Big Garden Bird Watch & an Encounter with Venus in the Evening

Birdwatching with the RSPB.

After a brisk, two-mile walk ’round Culcreuch Castle Estate with my youngest boy, I spent an hour spying garden birds in the mid-afternoon of Sunday January 26, as part of the RSPB Big Bird Watch, where participants were obliged to register their sightings online. It proved to be a reasonably fruitful endeavour, where I was able to record two Robins(one adult and the largest, most rotund youngster I’ve ever glassed), two Bluetits, a ‘battalion’ of Long Tailed tits(maybe 6-8 in all), one female Blackbird, and to top it all off, three large Magpies of which, I’m sure, once took up residence in my Rowan tree a few months back. The highlight for me this afternoon though was observing a big, imposing Cormorant perched majestically on a branch of a fallen tree at the far end of Culcreuch Pond, which I glassed earlier in the day during my walk. I’ve not seen Cormorants at the pond for quite a while; certainly not within the last few months, but nonetheless it was thrilling to see that it had either returned or decided to make its presence felt once again.

The day proved rather unstelled weatherwise, but just before sunset, the skies cleared and the temperatures dropped back towards their seasonal average(low single figures C). This would be a good opportunity to catch a sight of Venus, and sure enough, ’round about 5.45pm local time, during deep twilight, I sighted the planet, shining with its characteristic bright white hue, hovering above the conifer trees to my southwest. The pocket glass picked it up well, magnifying its splendour as a beacon in the evening sky, but not revealing much else of its secrets. I rushed inside and set up a better tool for that job; my 20 x 60 ‘giant’ binocular, mounted on a simple but very stable monopod, with which I was able to discern that the planet was a tiny gibbous form, enveloped in a thick layer of reflecting clouds.

Brilliant Venus in the southwest after sunset.

“Such a beautiful world,” I thought to myself, ” especially from the vantage of our clement home next door.” In reality, this earth-sized planet orbiting closer to the Sun than our own world, is as close to a living hell as is possible to conceive, with temperatures hot enough to melt lead, clouds laced with sulphuric acid and a thick, choking, light-bending atmosphere laden with carbon dioxide and particulate sulphur that is dense enough to crush human lungs in seconds. Some folk still(but not nearly as many as even a few years ago though) cling to the prospect of finding a world as clement as our own, way out there in the depths of space. They delude themselves into thinking that life can emerge naturally, from pond scum, and will thus be widespread throughout the galaxy.

Fanciful indeed!

Not in a billion light years!

nota bene: I discovered that Wrens can and do nest on river banks. My guidebook tells me; “the male builds 5-8 nests in hollows, crevices or holes in banks, walls or trees.”

There you go, straight from the horse’s mouth lol!

To be continued…………………………………..

 

De Fideli.

Spectrum

Take a Closer Look.

 

 

In this blog, I’ll be exploring subjects of general interest/concern to me and wider society in this age of mass deception:

The Dark Side of Transgender Medicine

 

How the Media Manipulates Truth

 

Cogito ergo sum

 

The Secular Case Against Homosexuality

 

Our Fragile Home

 

The Anti-Social Network

 

A Form of Child Abuse

 

Cool stuff you never hear in Church

 

The Rise of Homeschooling

 

James Clerk Maxwell: a Great Life Lived

 

Reasonable Faith: An Interview with Professor Alvin Plantinga

 

Doubting Dodgy Science

 

Evaluating World Views

 

Depraved Minds

 

The Beauty of the Creation

 

The Preciousness of Free Speech

 

Walking your Way to Good Health

 

Did the Eye Really Evolve?

 

Unholy Alliance: when Dodgy Science Merges with Theology

 

The Truth about UFOs

 

The Rise of Neo-Paganism

 

From Spiritual Shipwreck to Salvation

 

The Rise in Euthanasia Killings

 

The Greatest Story Ever Told

 

Holocaust Survivor

 

Coming Soon to a Town Near You: The Rise of Bestiality

 

The Death of Naturalism

 

Anything Goes

 

From Gaypo to Paedo

 

When Scientists Lose the Plot

 

The Sixth Mass Extinction Event in Our Midst

 

‘Depth Charging’ the Values of the Ancient World

 

The Truth about the Fossil Record

 

AI

 

The Language Instinct

 

Not the Same God

 

Greening the Deserts

 

Moving the Herds

 

Evolutionary Atheist gets his Facts Wrong…..Again

 

Distinguished MIT Nuclear Physicist Refutes Scientism

 

Pursuing Truth

 

The Dangers of Yoga

 

Pseudoastronomy

 

Get thee right up thyself! : The New Transhumanist Religion

 

The Biblical Origin of Human Rights and why it’s a Problem for Atheists

 

A Closer Look at the Israeli-Palestinian Conflict

 

Winds of Change: Prestigious Science Journal Concedes Design

 

A Distinguished Chemist Speaks the Truth

 

The Scourge of Pornography

 

Eye

 

Bart Ehrman Debunked

 

An Evil Generation Seeks After a Sign

 

Magnetic Pole Shift

 

Decimation of Global Insect Populations

 

The Spiritual Suicide of a Once Christian Nation

 

Mass Animal Deaths Worldwide

 

Not Going Anywhere

 

UN Report: World’s Food Supply under ‘Severe Threat’ from Loss of Biodiversity

 

False gods of the New Age

 

From Abortion to Infanticide in the “Land of the Free”

 

Sports Personalities Speak Out Over Transgender Athletes

 

Magonus Sucatus Patricius

 

Celebrating a Killing

 

Human “Out of Africa” Theory Debunked

 

The Other Side of the Rainbow

 

Vintage James Tour: How to Cook Up a Proto-Turkey

 

Big Brother Watching

 

Follow the Evidence: The Problem of Orphan Genes

 

Follow the Evidence: The Genius of Birds

 

The Butterfly Enigma

 

Man’s Best Friend

 

Darwinian Evolution On Trial Among Biologists

 

New Fossil Finds Thwart Human Evolutionary Predictions

 

Global Persecution of Christians

 

 Ratio Christi

 

Questions About the Qur’an

 

Engaging with Islam

 

Calling Evil Good

 

Parousia

 

Tall Tales From Yale: Giving up Darwin.

 

More on the Proto-Turkey:  Dr. Tour Responds to Cheap Shots from the Pond Scum Merchants

 

Good Riddance: Despicable British TV Show Axed after Death of Participant

 

There’s Heehaw Out There…ken.

 

The Fastest Growing Insanity the World has Ever Seen

 

Pharmakeia

 

Darwinism & Racism: Natural Bed Fellows

 

The Modern Root of Anti-Semitism

 

Jesus & Archaeology

 

A Victory for Common Sense: Transgender Weightlifter Stripped of his Medals

 

The US Equality Act: A Plea for Caution

 

Reunited: Music & the Human Spirit

 

Gladys Wilson

 

1st Century Christian Insight: The Didache

 

The Clothes Maketh the Man

 

Why Some Books were Left Out of the Bible

 

Why the Human Mind is not Material

 

What God Thinks of Scientific Atheism

 

For the Love of the Creator

 

An Essential Component of a Modern Education

 

Peace Cross

 

Earth: “Presidential Suite” of the Universe

 

How to Really Stand Out in a Crowd

 

Straight from a NASA Scientist: Jewel Planet

 

The Singularity

 

No Life Without Super Intelligence

 

Darwinism as a Cargo Cult

 

Body Plan Development Raises New Headaches for Evolutionists

 

Membrane Biochemistry Stymies Evolutionary Origin of Complex Cells

 

Science Speaks: Common Abortafacients Harmful to Both Mother & Child

 

Biblical Ignoramus Twists the Words of Christ

 

The Multiverse: Just Another Religion

 

Apologia Part I

Part II

Part III

Part IV

Part V

Part VI

 

Attention Parents: American Psycho Association Promoting Polyamory to Pre-Teens as ‘Ethical.’

 

The Only Rainbow God Recognises

 

Calling Time Out on Evolutionists’ Failure to Explain The Cambrian Explosion

 

7 Reasons to Reject Replacement Theology

 

Psychiatric Diagnoses are ‘Scientifically Meaningless’ Study Shows

 

Out of a Far Country: A Gay Son’s Journey to God

 

Universalism Debunked

 

The Prosperity Gospel Debunked

 

New Science Reveals First Cellular Life to be “Amazingly Complex”

 

New Law Firms Being Established to Counter the Rise in Christian Persecution

 

Playing the Numbers 32:23 Game

 

Multiple Lines of Scientific Evidence Converge on 3rd Century BC Age of the Famous Isaiah 53 Scroll.

 

Meet the Gestapo

 

Exposed: Theologians Deceived by Darwinian Ideology

 

New Insights into the Shroud of Turin

 

What we Know and Do Not Know About the Human Genome

 

Debunking Da Vinci Code Tosh

 

Sorry: No Such Thing as “Gay” Penguins

 

Genetic Entropy

 

Dunderheid Alexa

 

The Extinction of Reason

 

A Biblical Perspective on Diet

 

Revelation: Number of Transgender People Seeking Sex Reversals Skyrockets

 

Psychologist Debunks Pseudoscientific Explanations for Human Love & Compassion

 

The Dismantling of the Feminine

 

Disturbing Trends in the Roman Catholic Church

 

N = 402

 

The Nazareth Inscription

 

A Christian Response to Halloween

 

Seeking Methuselah

 

Beware the Enneagram

 

No Safe Spaces!

 

Pale Blue Dot

 

Encyclopedia Galactica

 

Phillip E. Johnson: A Tribute

 

The Darwinian Response to Human Life: Let the Baby Die!

 

The Best Explanation for Beauty

 

What is Feminism?

 

Insects & Light Pollution

 

Candy-Ass Christianity

 

Antiobiotic Resistance in a Post-Darwinian World

 

Adam & Eve: Redux

 

Joyce Meyer

 

Michael Behe Says No to Theistic Evolution

 

New Atheism: An Autopsy

 

Serenading an Old Girl.

 

“Progressive” Christianity as a Political Cult.

 

Israel Folau Vindicated

 

The Church of Satan, Sweden

 

A Rational, Christian Response to Humanism

 

More Depravity: the Sexualisation of Children

 

Shameful Humanity:  Murder of the Unborn Now the Biggest Worldwide Killer.

 

Origin Stories

 

Privileged Planet

 

Brokeness

 

Sorry Sam Smith, You’re Still a ‘He.’

 

Nature Genetics: How ‘Evolutionary Thinking’ led Biologists Astray about Pseudogenes.

 

A Kindgom Divided Against Itself: Why Evolutionary Psychology is Bunk

 

Of Melting Glaciers and Darwinism

 

First US President Addresses 47th March For Life, as theSecular Media Duck for Cover

 

Wolves Among the Sheepfolds

8 x 42 vs 8 x 32; Which is More Versatile?

Two good binoculars: The Barr & Stroud Savannah 8 x 42(left) and the Celestron Trailseeker 8 x 32(right).

I’ve been spending time comparing and contrasting the performance and ergonomics of two popular-sized roof prism binoculars; the venerable 8 x 42 and the smaller and lighter 8 x 32.

Which model is more versatile?

Tune in soon for an in-depth assessment ……………………………

 

De Fideli.

The War on Truth: The Triumph of Newtonianism Part II.

Taking the aperture advantage in grab ‘n’ go astronomy.

Continued from Part I

New entries indicated by ***

Of late I have been observing primarily with my 8” f/5.9 reflector.  After collimation, I check the seeing via visual observation at moderately high power on tight and/or magnitude contrast doubles—this is how I happened on this pair of doubles in Draco.

STT 312AB and STF 2054AB appear to the naked eye as the single star Eta Draconis.  Starting in Ursa Minor, a straight-line path from Kochab through Pherkad gets me to Eta as shown in the annotated Cartes du Ciel screenshot below.

 

DRADblDblPath_GIMP.jpg

 

I like to start with the fainter pair, STF 2054AB which is  a mere 12’ due North of Eta Draconis.  In 2017 this mag 6.2/7.1 pair had a separation of 0.943”, which is in line with historical speckle data.  At 345x, I saw two whitish stars of slightly uneven magnitude that were clearly split with dark space between the stars.  I gauged the seeing by estimating how often the image sharpens to two distinct discs.

The 2nd Ed. of CDSA lists STF 2054 as a (2) + 1 triple, meaning the A component is really AaAb.  Stelle Doppie informs the AaAb pair is CHR 138AaAb with a separation of 0.222” (1990)—perhaps those with larger glass can see this as oblong?

Moving on to the brighter object, Eta Draconis or STT 312 AB is where the fun starts.  This mag 2.8/8.2 pair has a separation of 4.68” as measured by Gaia satellite (2015.5)  Using the same eyepiece you used for STF 2054AB, try to find the faint secondary without prior position angle knowledge.  It will be quite small and about 4.5x farther than the distance between the stars comprising STF 2054AB. 

My first attempt at detecting STT 312 B required almost a half hour of moving my eye from averted to direct vision before I definitively saw the tiny speck of light corresponding to the companion.  On a subsequent night, I found the secondary right away because I knew where (and how) to find it.  The more steadily the diminutive B presents as a dot of light, the better my seeing.  Of course, darker skies will also aid your efforts for seeing the faint companion. 

STF 2054AB and STT 312AB help me gauge my local seeing and are fun to look at.  Have you looked at these stars lately?

Nucleophile(Austin, Texas, USA): from an online thread entitled, Fun in Draco: Proximal Pairs STT 312AB and STF 2054AB

Perhaps the aforementioned objects are too easy and you desire a greater challenge; if so, head about 11 degrees due south of Eta Draconis to Hu 149

This pair of ~matched magnitude 7.5 stars has a separation of 0.66″ (last precise in 2017 = 0.665″; my own measure in 2017 = 0.662″)  The pair are slowly widening:  Burnham (1978) lists the separation at 0.5″

Using my 8″ reflector, I observed this object last night and logged the following observations:

345x:  image transforms from elongated to notched (snowman) about 30% of the time; both stars are light orange-yellow

460x:  now seen as sitting on the border of resolved to two discs and split with the tiniest of black space between the discs

Below is an inverted image of Hu 149 I assembled in 2017 using my 15″ reflector and an ASI178MC camera at f/23 operating in mono mode.

 

HU149_JDSO.jpg

Nucleophile(Austin Texas, USA), from an online thread entitled; Fun in Draco: Proximal Pairs STT 312AB and STF 2054AB

Attached are some recent pictures of these double stars.  In all cases, N is up and E is left.

I obtained the images using my 15″ reflector and an ASI 290MM cooled CMOS camera.  An imaging train of Paracorr type 1 (setting 5), Powermate 2.5x and a Baader Orange filter gives an f ratio of 13.3  Images were collected using either SharpCap or Firecapture. 

Measures were made with Speckle ToolBox.  Composite images were assembled in Registax.

First up is STF 2054AB

STF2054AB_DRA.jpg

Dear Mark,

Thanks a lot for your interesting and well-documented presentation of a pair of doubles so well suited to gauging seeing  all year round. Last night I made these my first port of call with a 140mm Maksutov (an OMC 140 made by Orion UK, a good instrument). The physics suggest that the separation of 0.943” which you state for STF 2054AB is at the physical limit possible with this aperture, so I was keen to find out how I would fare.

The day had been hot, seeing was mediocre. I know from experience, though, that the air may calm down in certain phases of the evening, so I just hoped I would catch a good moment. At 75x I saw no hint of a companion of Eta Draconis, but STF 2054AB was definitely elongated. At 130x still no sign of Eta’s companion, but the elongation of STF 2054 became even more evident and it was clear at which end the weaker component stood. Encouraged by this, I went up to 210x. Now STF 2054 was a stretched figure-8 that popped apart into separate discs in better moments of seeing. Somehow quite charming!

I had gone in without PA knowledge and estimated this at 330°. Stelledoppie says 351°. So deviation <10%, that’s OK.

After having trained the eye in this manner, I turned my attention to Eta Draconis at 210x. All I could spot was a disc within a wildly dancing diffraction pattern. Although the B component, with its separation of 4.68”, is more than 4.5x further than the distance between STF 2054 A and B, it is evidently much harder to spot. This was an interesting lesson in the effect of Delta-Mag.

I find STF 2054 quite charming and Eta quite challenging, and will certainly be returning to them often. So thanks again, Mark.

CS, Christopher

C.Hay(Germany), from an online thread entitled; Fun in Draco: Proximal Pairs STT 312AB and STF 2054AB

Finally, here is Hu 149

I measured this one 21 times over three nights in order to gauge repeatability of the measuring protocol.  The current measure matches very well what I obtained a few years back.

Hu149_DRA.jpg

rugby, on 19 Jun 2019 – 06:11 AM, said:

I just finished observing STF 2054 AB and STT 312 in Draco using an  SW 120 ED and a Meade LX 10. A very bright moon with Jupiter brightened the eastern horizon.  Unfortunately these pairs lie directly above my house and thus suffer from heat rising from the roof.

What I saw was surprising. 2054 was elongated but not separated in the 120 at 200x.  I had not expected anything because it is on the edge of this scope’s capabilities. I did not try the 8 inch.

STT 312 AB was exceedingly difficult. Without prior knowledge of PA I kept seeing flashes of a tint dot south south preceeding the primary. I used the 120 at 200x. The view in the 8 inch was too turbulent for any resolution.

I am notoriousy poor in estimating position angle.

Hi Rugby,

Give ’em a try with your 8″–I think you will like the views!

Nucleophile( Austin Texas, USA), from an online thread entitled; Fun in Draco: Proximal Pairs STT 312AB and STF 2054AB.

Last night was about my 10th try to find that little bugger hanging out in the diffraction ring. I had tried repeatedly and without success with my 120mm ED. I’ve tried before with my 8″ [Newtonian], even on an EQ platform a few nights ago. This time I managed to see it with the 8″ at an ungodly 498x without the EQ, so constant nudging and then allowing it to drift (if the drifting was near rapids) . I would call it my “great white whale”, but it’s more like a tiny white pimple.

You’d expect the 8″ should easily split it, if I could just get improved seeing.

Chesterguy

Chesterguy( Stillwater, Oklahoma, USA), from an online thread entitled: Zeta Herculis…finally!

 

Well, I confirmed my sighting of Zeta Herculis las night. Same instrument, equal or better seeing and this time on my EQ Platform. Despite not getting my platform aligned perfectly on Polaris because it was blocked by my house, I still managed enough accuracy so that, while it drifted through the EP, it wasn’t like the prior night. Still a tough split at 498x in my typical seeing. I salute those of you who are splitting it below 140mm.

Chesterguy(Stillwater, Oklahoma, USA), from an online thread entitled: Zeta Herculis…finally!

I observed this double with the 8″ reflector twice in recent days:

345x:  just split with smaller secondary appearing yellow against bright white primary; secondary appears to be sitting between first and second diffraction rings

314x:  when seeing permits, the yellowish secondary is seen sitting atop the primary

I did a few Aberrator simulations for the expected view using either my 8″ or 15″ reflectors; these are shown below.

 

ZetHERAberrator_Gimp.jpg

The 8″ inch simulation is fairly close to what I saw.  The 15″ simulation shows the secondary now sitting near the second diffraction ring.  In some images I obtained recently with the 15″ and an ASI 290MM camera this is pretty much what I saw.  In the composite image below the first diffraction ring appears as a fuzzy halo while second ring got washed out a bit in processing.

 

STF2084_Zeta_HER.jpg

Nucleophile(Austin, Texas, USA), from an online thread entitled; Zeta Herculis…finally!

I just made a 7 inch aperture stop today for my 18. Worked great tonight. I’ve made them many times before but it’s been a while. Seeing tonight was so good the better views were at full aperture..

Darren Drake(Chicago, USA), from an online thread entitled Aperture Mask

DavidC, on 19 Jun 2019 – 03:41 AM, said:

I am making an off axis aperture mask for my 10 inch lightbridge, but using a single 4 inch hole. I got the idea from san francisco sidewalk astronomers, but they had it as plans for a solar filter. I’m making it for planets and double stars. I’ve been told by stepping the aperture down to 4 inches, planets won’t be as bright, therefore I can use more power on them. At 1270 mm focal length, I’m hoping for impressive views on planets by using more power. Am I thinking this correctly?

 

Thanx, David

Waste of time IMO. I have a 10” LB with a very good mirror set. I also have excellent 100 and 120 mm ED refractors. If seeing is equal, the 10” reflector slaughters the excellent refractors in planetary detail.

SteveG(Seattle, Washington, USA), from an online thread entitled: Aperture Mask

Vla, on 20 Jun 2019 – 2:55 PM, said:

Smooth edges have more of a cosmetic effect. Rough edges don’t induce aberrations, because they don’t affect wavefront shape, and unless the edge is ridiculously rough, the diffraction effect will be negligible. As an illustration, effect of a 2-inch focuser protruding into the light path of a 200mm diameter mirror. As much as 1 inch into the light path will take only about 1% of the energy out of the central maxima (which, expectedly, becomes somewhat elongated, because the vertical mirror diameter is effectively shorter).

Yes indeed! The effects are diffractive and tiny, not what we optics guys call aberrations. I also like your focuser signature there… Fourier Transform (impulse-response) says it all.

Masks roughly-cut with scissors or a knife are perfectly fine. The one thing to try to avoid is long straight edges. Those will give noticeable spikes. The three straight edges of the focuser there… do a little bit of that.

On the tech/theory side… there are infinitely many wavefronts that will produce the same impulse response. That’s because the sensor (eye or camera) detects only amplitude, but not phase. So you can’t inverse-transform back to the wavefront by processing on the one image of a star… unless you use two or more (ideally many) focus positions’ images. And that is what we call ~phase diversity analysis~ (what was used to assess Hubble’s flaw). And what is implicitly involved in the various casual ~Sar Tests~ that we often talk about here. 

Tom Dey(Springwater, New York, USA), from an online thread entitled: Aperture Mask

Deep13, on 14 Dec 2018 – 06:56 AM, said:

In my mind, the ideal planet telescope is a 10 or 12″ EQ Newt (split ring?) in a permanent location with a clear view of the south and overhead. Add a good binoviewer, pairs of long ZAOs, and an easy way to reach the EP, and I’d be all set. In reality, it would be too expensive and I have no place to set it up permanently. So-o-o-o, I’ve arranged to buy a used 8″ f/8 EQ-mounted Newt. I’ll need to have some servicing done on the mirrors. I’m thinking that within the realm of likely possibility, this may very well be my ideal set-up. Right now it has no fan and a tall R&P focuser, so I may change those things. And I’ll built a cart for the Meade RG mount. I already have a tall adjustable chair and a Denk II with pairs of TV Ploessls.

 

Any thoughts? What’s your ideal planet scope?

 

I had both a very good 8″ Zambuto f-7.5 and a 10″ Waite f-5.8 on an EQ mount, the 8″ I had rotating rings but still a very big pain in the rear to use on an EQ mount. I am considering a slightly different set up 10″ f-5.3 through f-5.5 for a shorter tube and mounted on an EQ-AZ mount, in AZ mode viewing will be far more easier as the EP will be on one side and accessible.  At the focal lengths mentioned as long as you get a premium mirror and build it well you can achieve 50x per inch with sharp image on the planets, and you can use a 1.83″ secondary, CO 18.3%. good luck.

dag55(Hamburg, Illinois, USA), from an online thread entitled; Ideal Planetary Scope

The Orion 4.5 in f/8 dobsonian could be an option. Seems to get good reviews on the optics here on CN. Lightwieght. I believe the focuser is plastic, but, it should be ok with normal weight 1.25in eps.If the moon with a 4 -5 in reflector is the ojective, this little scope should do a decent job.I have not used the Orion, however, I do have a 4.5in f/8, and I think they are capable little scopes.

Good viewing,

dmgriff, from an online thread entitled, 4-5” reflector recommendation

 

+1 on the AWB OneSky.

I was surprised at how well it works. At 14 pounds total, it might be just what you’re looking for.

Havasman( Dallas, Texas, USA), from an online thread entitled: 4-5” reflector recommendation

The AWB One Sky is fine for the money but its burdened with an very poor helical focuser, preferable is the Lightbridge 130 , discontinued but still available from some dealers, the Zhumell 130, the best of the bunch IMHO or the slightly smaller Zhumell 114 , very similar to the Orion Starblast but less money, the Zhumell is also sold as the Edmund Astroscan Millenium, D.

Binojunky, from an online thread entitled: 4-5” reflector recommendation

 

The Onesky is a fine scope. I have no problem with the focuser.,and the mount is quite stable.,Some of my best spent astro money.,cheers.,

Attached Thumbnails

  • 20190327_183143.jpg

 

Clearwaterdave(Western Maine, USA), from an online thread entitled: 4-5” reflector recommendation

How is a 4″ apo a “no brainer” when the OP specificly asked about a reflector? The OP has other scopes and seems to have some idea of what he’s lookin for.,What scope you think would do a better job for doubles or planets is not what he asked about. If you have used and liked a 4-5″ reflector of any type and you want to share your experience here that would be helpful to the OP.,waytogo.gif

Clearwaterdave(Western Maine, USA), from an online thread entitled: 4-5” reflector recommendation

I have had the OS up next to a 102ed and “to my eyes” the views are too similar for me to say either one was “better”.,And there are many many very happy OS owners.,So yes.,you can expect a quality reflector for $200.,That’s the no brainer.,and the OS isn’t the only one.,there are a few good quality 5″ reflectors out there for $200.,YOMV.,

Clearwaterdave(Western Maine, USA), from an online thread entitled: 4-5” reflector recommendation

Thank you again for all the great responses. I’m always pleasantly surprised at the information you guys have and your experience. Yes, optics are my primary concern for the scope, but I haven’t really read one bad review concerning them so I think the OneSky is what I’ll go with. I have a pretty large back deck with a decent view to the south so it will be easy to track the moon every night, even if only for a few minutes. Concerning refractors: the truth is I have little experience with them (I know they’re not hard to figure out) and my comfort level, if you will, is with Dobsonian type reflectors. I have a neighbor down the road who has a 4” Takahashi (I think), and the views through it are really something else. Then he told me the price tag and my mind went to how how big of a Renegade or Teeter I could get for the same price. Plus someone told me that owning a refractor will lead you down to the perilous and very expensive road of astrophotography.
The reason I don’t put the 8” out on the back deck is that I use it specifically for planetary viewing now. I have it in the garage ready to load up for a quick drive into the foothills next to the house. The view is better and I get away from all the house and street lights. At f/7 that 8” gives just wonderful views of the planets. I was also able to complete the AL double star program with. If you haven’t looked at that program, I recommend it as it was one of my favorites to do. The 8” was the first scope I ever owned and I had to rebuild it out of disassembled parts, which I found at a flea market. That was a journey, let me tell me you. But now it’s dialed in with a great mirror and I’ll have it forever.
And with the 10”: that’s my deep-sky, dark site, fall into the heavens scope. I try to get out there at least once, if not twice, a week. It too has great mirror and makes it hard for me to financially justify a larger scope given there’s so much to see with it.
Back to the OneSky. Hopefully it will be what I’m looking for. I have perfect cover and place for it, it won’t get dirty, and when I’m out enjoying the late evening and want a quick peak, it’ll be right there.

Mick Christopher, from an online thread entitled: 4-5” reflector recommendation

One of my all-time favorite 4ish inch scopes is the Orion XT4.5, mentioned by Dave and Ed earlier. It’s a very nicely engineered and accessorized product, and provides sharp high power views with very minimal focus wiggles and immediate dampening times. The long focal length makes the scope forgiving of the somewhat imprecise focuser, which works quite well. It’s also very easy on simple eyepieces, which is handy. It’s not a do-all scope, owing to the focal length and 1.25″ ep limitation, but it’s still capable of providing pleasant low power views, yet shines at moderate and high powers. Add a 5 gallon bucket, inverted, as a “chair” (which can pull double duty as a caddy for charts, ep case, and binos) , and the scope works well for adults without the need to raise the scope on a platform.

KerryR( Midwest Coast, Michigan, USA), from an online thread entitled: 4-5” reflector recommendation

 

If the OP can handle the extra size and cost the Orion XT6″F8 is a fine scope, I picked mine up last years for $300 Canadian brand new shipped to my door, take it out in two pieces, plonk it on the ground and away you go, D.

Binojunky, from an online thread entitled: 4-5” reflector recommendation

 

This report is the third installment of a series of observational investigations I have made using an 8 inch f/5.9 reflecting telescope. 

Check out this link for goals and methods used in this study:

https://www.cloudyni…-and-monoceros/

Corvus
Bu 920 (12158-2321) mags 6.86/8.22; pa = 308°; sep = 1.934”, 2016 (solid data)
345x:  well split with secondary a bit smaller; both stars are yellow; well above resolution limit

B 1716 (12247-2004) mags 9.42/9.42; pa = 230°; sep = 0.701”, 2014 (solid data)
345x:  single star
460x:  a bit elongated, but never resolved despite best efforts; below resolution limit; important data point to set lower limit for fainter stars

Hydra
STF 1273 AB, C (08468+0625) mags 3.49/6.66; pa = 310°; sep = 2.824”, orbital estimate for 2019.3 (solid data)
345x:  easily split to two yellow stars of widely varying magnitude; above resolution limit

Bu 587 AB (08516-0711) mags 5.75/7.41; pa = 121°; sep = 1.186”, 2017 (solid data)
345x:  blur of light that sharpens to a small secondary that is just split
460x:  spit 100% of time; above resolution limit

Bu 219 (10216-2232) mags 6.70/8.52; pa = 186°; sep = 1.773”, 2015.5 (Gaia DR2, solid data)
345x:  split 100% of time; secondary is much smaller and both stars are white; above resolution limit

A 3064 (08403-1518) mags 9.15/9.00; pa = 357°; sep = 0.681”, 2015.5 (Gaia DR2, solid data)
345x:  just resolved to two tiny discs 40% of time; just above resolution limit; important data point to helps set minimum value of rho for faint, equal mag pair

A 338 (08207-0510) mags 8.83/9.39; pa = 17°; sep = 0.569”, 2015.5 (Gaia DR2, solid data)
345x:  slightly pointy
460x:  slightly elongated, but never resolved; well below resolution limit

HJ 4478 (11529-3354) mags 4.67/5.47; pa = 52°; sep = 0.578”, 2015 (data needs confirmation)
627x/orange filter:  elongated that becomes notched 10% of time; just below resolution limit; difficult due to low altitude; requires re-measure to firm up separation value

B 1175 (10582-3540) mags 8.25/9.23; pa = 251°; sep = 0.61”, 1998 (data is old, scant)
345x:  resolved 50% time to two similar magnitude yellow stars; a bit above resolution limit; separation likely greater now; requires newer measures of separation and delta mag

B 218 (12002-2706) mags 9.11/9.69; pa = 340°; sep = 0.472”, 2015.5 (Gaia DR2, scant data)
627x:  very faint; rod shaped at times, but no hint of resolution or notch; well below resolution limit; requires re-measure to firm up separation data

HWE 72 (12136-3348) mags 6.48/8.55; pa = 159°; sep = 1.231“, 2016 (solid data)
345x:  just split 30% of time to two white stars; secondary is much smaller; above resolution limit

Bu 411 (10361-2641) mags 6.68/7.77; pa = 303°; sep = 1.33”, 2017 (solid data)
345x:  just split 100% time to two light yellow stars of somewhat dissimilar magnitude; above resolution limit

Bu 219 (10216-2232) mags 6.70/8.52; pa = 186°; sep = 1.773”, 2015.5 (Gaia DR2, solid data)
345x:  split 100% time; secondary is much smaller and both stars are white; above resolution limit

Leo Minor
STF 1406, aka STT 211 (10056+3105) mags 8.37/9.42; pa = 219°; sep = 0.728”, 2017 (solid data)
345x:  just split from resolved 30% time; stars are faint, white, and seem to be of similar magnitude; above resolution limit; a newer delta mag measure desired

Lynx
STT 159AB (06573+5825) mags 4.45/5.50; pa = 236°; sep = 0.704”, orbital estimate for 2019.3 (solid data)
345x:  single star
460x:  possibly pointy
627x:  at times elongated showing secondary as smaller, but never resolved; below resolution limit; it is unclear why this is so difficult—perhaps there is a ‘brightness’ factor that needs to be incorporated?  Revisit next year using orange filter and get a new measure.

COU 2607 (07441+5026) mags 5.33/8.43; pa = 164°; sep = 0.973”, 2012 (data is a bit old but is considered solid)
460x:  secondary pops into view as just split 50% of time; just above resolution limit

STT 174 (07359+4302) mags 6.62/8.26; pa = 92°; sep 2.170“, 2015.5 (Gaia DR2, solid data)
345x:  split 100% of time; both stars are white and secondary is much smaller; fine mag contrast double; well above resolution limit

Hu 850 (08094+3734) mags 9.42/9.23; pa = 349°; sep = 0.57“, 2016 (scant data)
345x:  viewed for an extended period of time using averted vision shows the pair exhibiting a notch just past extended a mere 10% of the time; never resolved and is considered below the resolution limit; a re-measure of separation is needed

Ursa Major
STT 232AB (11151+3735) mags 8.02/8.90; pa = 243°; sep = 0.623”, 2015.5 (Gaia DR2, solid data)
552x (Pentax 2.5XO/Paracorr Type 1, setting 1):  pointy about 25% of time, but never a hint of being resolved; below resolution limit

STT 235AB (11323+6105) mags 5.69/7.55; pa = 44°; sep = 0.949”, 2019.3 (orbital estimate, solid data)
345x:  on the resolved/split border with secondary seen as much smaller
460x:  cleanly split; primary is yellow, secondary is light orange; above resolution limit

STF 1770 (13377+5043) mags 6.93/8.18; pa = 128°; sep = 1.722“, 2015.5 (Gaia DR2, solid data)
345x:  cleanly split; primary is light yellow while the smaller secondary is light orange—a fine pair; above resolution limit

STT 200 (09249+5134) mags 6.53/8.57; pa = 337°; sep = 1.251”, 2015.5 (Gaia DR2, solid data)
345x:  close split (AV helps to see fainter secondary)
460x:  easily split to two stars of unequal magnitude—very nice; above resolution limit

STT 232AB (11151+3735) mags 8.02/8.90; pa = 243°; sep = 0.623“, 2015.5 (Gaia DR2, solid data)
552x (Pentax 2.5XO/Paracorr Type 1, setting 1):  pointy about 25% of time, but never a hint of resolution; below resolution limit—important data point for calculator development

A 1346 (09591+5316) mags 8.84/9.66; pa = 179°; sep = 0.624“, 2019.3 (orbital estimate; data is incongruent between orbital estimate, historical speckle and Gaia DR2)
345x:  slightly elongated; very difficult
460x:  moves past elongated to notched <10% of time
627x:  possibly seen as resolved 10% of time with averted vision; just below resolution limit; requires re-measure to firm up separation value

STT 229 (10480+4107) mags 7.62/7.92; pa = 254°; sep = 0.63“, 2019 (estimate from 4th Interferometric Catalog; data incongruent between historical speckle, orbital estimate and last precise)
345x:  moves past pointy to resolved 30% of time showing secondary as a bit smaller versus the primary
460x:  persistent snowman shape that sharpens to nearly split 30% of time; just above resolution limit; re-measure of separation needed for this important data point

Bu 1077AB Dubhe (11037+6145) mags 2.02/4.95; pa = 336°; sep = 0.802“, 2019.4 (orbital estimate, solid data)
460x/orange filter:  very difficult; secondary pops into view 30% of time as just split—otherwise, it is merely a blur of light/brightening of first diffraction ring; at or just above resolution limit

**Have you observed or imaged any of these objects recently?  Let me know.  Perhaps you have a suggestion for a double I should observe—I’m all ears!

Nucleophile(Austin, Texas, USA), from an online thread entitled; Investigations With an 8 Inch Reflector. Part I: Canis Major, Canis Minor, Lepus, and Monoceros

My preference is in the “or” category. I have used all of my scopes for doubles, but I love my 10 inch reflector… it is a double star magician… except for Sirius B… just can’t get that one in the 10 inch. But I have split it ONCE with my 4 inch achro (retired this one to give to my granddaughter)… she loves doubles too…

SeaBee1, from an online thread entitled; scope preference for doubles

I use my Stellarvue 105mm APO most of the time for doubles wider than 1″ and when the seeing is only fair.  It gives such nice images with no central obstruction.

If the seeing is above average I use the Intes 180mm Mak-Cass with its astro-sital 1/9 wave optical system on the tighter doubles, and planets.

I don’t usually use the 10″ LX 200 on doubles, but one night when the seeing was very good I was using the Baader 8-24 zoom on the double double in Lyra and zoomed all the way to 660x,  the stars looked perfect and the separation was enormous.

I usually don’t use my 18″ Obsession for doubles, but once while doing a two star alignment on Antares with my 12.5mm cross-hair eyepiece, there it was a bright orange star with a little green orb next to it.  I hade to just stop and take a good long look, it was beautiful, and so was the seeing that night.

Astromaster; from an online thread entitled; scope preference for doubles

Last seen this star for a long time. Seeing that the closer stars that I knew are either already inaccessible (too close) or have gone beyond the horizon, I decided to observe those that are less mobile. In particular, this one. Since there are days with an excellent atmosphere and they should be used. In comparison with the double in the zet boo, this star looks obviously wider and accessible. It is interesting that the difference in the sizes of fragments of diffraction disks is visible. This is quite unexpected, considering that the difference in brightness is only 0.2. Maybe this star is variable? and therefore I see that parts of diffraction discolves of different sizes (this happens when the difference in brightness is more than 1 … 1.5 magnitudes). This is weird.  I used a large piece of paper to accurately mark the track of the star and its position. Such dimensions allowed me quite accurately, without using devices, to note how exactly the disc is stretched..eta crb1.png
Constantin 1980, from an online thread entitled: Observation Eta CrB (0,38 “) 9\04\2019

This report is the fourth installment of a series of observational investigations I have made using an 8 inch f/5.9 reflecting telescope. 

Check out this link for goals and methods used in this study:

https://www.cloudyni…-and-monoceros/

Bootes
BU 224 (14135+1234) mags 8.94/9.35; pa = 95°; sep = 0.65“, 2015 (last precise; not solid, opening)
345x:  single star
460x:  pointy but never resolved; well below resolution limit; magnitude data is from Hipparcos (1991, 515nm); needs a re-msre of delta mag and separation

 

STT 287 (14515+4456) mags 8.40/8.62; pa = 5°; sep = 0.575“, 2017 (last precise vs 0.659” orbital estimate for 2019.3; data incongruent)
345x:  seen as elongated 30% of time
460x/averted vision/extended viewing:  elongated only, never resolved; below resolution limit; needs a re-msre of separation

 

STF 1866 (14417+0932) mags 8.48/8.65; pa = 205°; sep = 0.733“, 2015.5 (Gaia DR2, solid data)
345x:  on the border of resolved and split to two even magnitude light yellow stars; above resolution limit

 

STF 1863 (14380+5135) mags 7.71/7.80; pa = 60°; sep = 0.654“, 2017, (last precise, solid data)
460x/orange filter/averted vision/extended viewing:  moves past elongated to resolved 20% of time
627x/orange filter: just resolved 50% of time; just a bit above resolution limit; important data point (equal mag pair) to set minimum value of rho

 

STF 1867 (14407+3117) mags 8.36/8.83; pa = 355°; sep =0.674“, 2017 (data needs confirmation)
460x:  just split 50% of time to two white stars of slightly dissimilar magnitude; need re-msre of separation

 

A 148 (14220+5107) mags 8.32/8.96; pa = 190°; sep = 0.535“, 2019.3 (4th Int. Catalog estimate vs 0.58” last precise in 2015; data not solid)
627x:  a bit elongated but never resolved; well below resolution limit; need re-msre of separation

 

KUI 66 (14148+1006) mags 5.44/8.43; pa = 111°; sep = 0.99“, (my own measure in 2017 with ASI 178MC camera; data tentatively considered solid as it is a match with 4th Int. Cat. estimate)
627x/orange filter:  much smaller secondary seen as a resolved dot very near first diffraction ring 30% of time; just above resolution limit; important, large delta mag data point so re-msre with ASI 290MM camera needed.  See image below.

 

AGC 6 (14339+2949) mags 9.81/10.30; pa = 133°; sep = 0.752“, 2015.5 (Gaia DR2, solid data)
345x/extended viewing:  seen as elongated rod, never resolved; very faint and difficult; below resolution limit; important data point to set ‘faintness factor’

 

STT 298AB (15360+3948) mags 7.16/8.44; pa = 187°; sep = 1.208“, 2019.4 (orbital estimate, solid data)
345x:  easily split to two small light yellow stars of similar magnitude; very pretty; above resolution limit

 

A 1110AB (14497+0759) mags 7.69/7.93; pa = 245°; sep = 0.692“, 2015.5 (Gaia DR2, solid data)
345x:  oscillates between resolved and split; both stars are yellow with secondary seen as smaller and *delta mag is likely >0.24
460x:  seen as split 100% of time with secondary possessing a hint of orange; above resolution limit; Gaia DR2 gives a delta mag of 0.67 which does not agree with Tycho value of 0.24—will attempt a measure of delta mag to rectify

 

Canes Venatici
STF 1606 (12108+3953) mags 7.44/7.93; pa = 145°; sep = 0.611“, 2019.3 (orbital estimate vs 0.627”, last precise in 2017; data not solid)
460x:  elongated but never resolved
627x:  moves past notched rod to resolved 20% of time; at or just above resolution limit; observation supports tighter value of rho [0.611”]; this is an important data point; will re-msre (possibly annually) to firm up value

 

STT 251 (12291+3123) mags 8.35/9.27; pa = 61°; sep = 0.781“, 2017 (last precise; data not solid)
345x:  just resolved 30% of time with secondary much smaller
460x:  just split 50% of time; a bit above resolution limit; faint secondary plays role in difficulty; re-msre of separation needed

 

STF 1768AB (13375+3618) mags 4.98/6.95; pa = 95°; sep = 1.656“, 2019.3 (orbital estimate; solid data)
345x:  well split, primary is white and secondary is light yellow and considerably smaller—a fine sight!  Above resolution limit

 

Coma Berenices
STF 1639AB (12244+2535) mags 6.74/7.83; pa = 324°; sep = 1.855“, 2019.3 (orbital estimate; solid data)
345x:  well split, primary is white and secondary is light yellow; very pretty mag contrast pair; above resolution limit

 

STF 1687 (12533+2115) mags 5.15/7.08; pa = 200°; sep = 1.18“, 2018 (last precise; solid data)
345x:  a bit past just split 100% time with secondary noticeably smaller; both stars are yellow; above resolution limit

 

COU 397 (12575+2457) mags 9.06/9.71; pa = 63°; sep = 0.70“, 2015 (last precise; solid data)
345x:  single star; faint!
460x/averted vision:  slightly elongated but never resolved; below resolution limit; important data point to establish ‘faintness factor’

 

A 567 (13328+2421) mags 6.21/9.71; pa = 256°; sep = 1.450“, 2015.5 (Gaia DR2, solid data)
345x:  secondary seen as split 50% time and appears as very small, very faint dot a bit past first diffraction ring of primary; above resolution limit

 

Ursa Minor
STF 1989 (15396+7959) mags 7.32/8.15; pa = 23°; sep = 0.67“, 2013 (last precise vs 0.603”, orbital estimate for 2019.4; data not solid)
345x:  moves past elongated to exhibit a snowman shape
460x:  resolved about 40% time with secondary a bit smaller; above resolution limit (observation supports separation closer to 0.67” value; re-msre of separation needed)

 

BU 799AB (13048+7302) mags 6.60/8.45; pa = 265°; sep = 1.39“, 2017 (last precise; solid data)
345x:  easily split; both stars are white and secondary is considerably smaller—very pretty; above resolution limit.

 

A 1136 (16135+7147) mags 9.22/9.47; pa = 9°; sep = 0.727“, 2007 (last precise, data is old)
345x:  barely split; both stars are very small and white, and secondary is just a bit smaller; helps to establish ‘faintness factor’; above resolution limit; a re-msre of separation is needed

 

Virgo
BU 797AB (12345+0558) mags 9.10/9.39; pa = 146°; sep = 0.61“, 2010 (last precise, data is a bit old but considered solid)
345x/averted vision/extended viewing:  slightly pointy
460x:  elongated and on the border of resolved, but never did resolve despite an extended view
627x:  moved past elongated to resolved about 5% of time; at or slightly below resolution limit; a very important data point that warranted 45 mins of study under very good seeing conditions

 

RST 4484 (11447-0431) mags 8.46/8.39; pa = 64°; sep = 0.738“, 2017 (last precise; data not solid)
345x:  just split to two ~even magnitude yellowish-white stars—beautiful!  Above resolution limit; re-msre of separation needed

 

BU 935AB (13459-1226) mags 5.66/8.47; pa = 304°; sep = 1.03“, 2001 (last precise; data is old)
460x:  brightening of first diffraction ring sharpens to much smaller secondary 30% of time; both stars are yellow; above resolution limit; a new measure of separation is needed for this important mag contrast binary

Have you observed or imaged any of these objects recently?  Let me know.  Do you have a suggestion for a double I should observe within one of these constellations?  I would like to hear about it.

Nucleophile(Austin, Texas, USA), form an online thread entitled, 8 Inch Reflector Investigations. Part IV: Bootes, Canes Venatici, Coma Berenices, Ursa Minor, and Virgo

Here is an image of KUI 66 I obtained in 2017 using an ASI178MC camera operating in mono mode.

 

KUI66_JDSO.jpg

Cool, another crop! Here’s some of mine for comparison:

STT 287, 552x 12.5”. Wow! Hair-split, ~0.7″, near equal or half a delta mag.

STF 1867, 552x 12:5”. 0.5 delta mag, hair to figure 8 split, white. Not especially good seeing

Kui 66: 12.5” Unresolved faint haze at 553x, but adding the apodizing mask I had a glimpse of the B star 15% of the time, very small and faint, ~3″ and 4-5 delta mag. Both orange. Definitely there.

STT 289: 8″ 205x: Noticed a very much fainter star emerge with averted vision then could hold direct. Very fine, well split. 8″ 410x: Tried to bring out the B star with higher magnification, but oddly it disappeared. Curious. 20″ 410x: B star easily seen though the disks are bloated, seeing not good.

STT 298. 12.5” 552x Wow! Almost didn’t look at this one since it was split in the 80mm finder. One component is a close equal pair, ~2″.

STT 251. 12.5” 553x: Decidedly not round disk — there’s also a brightening in the diffraction — but not really split.

STF 1768: 8″ 205x: Very tight pair, a little more than hairline split, ~2 delta mag. 8″ 333x: white and dull blue, ~1″, split, Nice!

STF 1768. 12.5: 553x: Very pretty pale yellow and orange, 2-3 delta mag, ~2″

STF 1639: 8” 205x White and slightly blue pair; close, around 3″ [overestimated the split, it was so clean!]

STF 1687: 12.5” 553x = 35 Com: Bright orange & fainter B, showpiece, ~1.5″

A 567: 12.5” 553x: very faint B, very close, ~1″ when seeing stills, 3-4 delta magnitude. Surprised it is not so difficult. B looks like it doesn’t have any light of its own and is illuminated by A.

BU 935 = 86 Vir: 12.5” Pretty orange star but @ 553x poor seeing won’t allow split of 3 delta mag, 1.2″ B.

mccarthymark(San Francisco Bay Area, California, USA), form an online thread entitled; 8 Inch Reflector Investigations. Part IV: Bootes, Canes Venatici, Coma Berenices, Ursa Minor, and Virgo

Excellent info, Mark.

my notes on your notes:

a.  STT 287, inclined to think it is tight–like 0.6″  I will def msre next year.

b.  the much studied KUI 66, nice use of mask to glimpse the companion!  I used an orange filter and very high power on an excellent night

c.  STT 289–I will add this large delta mag object to my list (thanks!)

d.  STT 298AB  something is askew here with the delta mag as both of us describe the mags as being similar–I didn’t catch this first time around but have made a note for next year to try and get a msre of delta mag for this one; I looked back into my log notebook and also noted:  “tiny headlights; beautiful!”  Additional note based on the 4th Int Cat.:  the same year as the Tycho mag values [as listed in the WDS] are those from Hipparcos (albeit at a slightly shorter wavelength = 511nm) which found  the magnitudes to be 7.59 and 7.78–a much closer match to what we observed.  This is humorous:  WDS notes say the ‘D’ component at 167″ is actually a galaxy (possibly a quasar)!  How’s that for ‘optical illusions’  At mag 14, I will be chasing that one for sure with the 15″ scope.

e.  STT 251 was surprisingly difficult for both of us…

f.  BU 935  you may wish to give this one another shot on a night of very good seeing; it is difficult

Nucleophile(Austin, Texas, USA), form an online thread entitled, 8 Inch Reflector Investigations. Part IV: Bootes, Canes Venatici, Coma Berenices, Ursa Minor, and Virgo

Here is a composite image of A 1110AB taken in 2017 with the ASI 178MC camera.  The image supports a delta mag of >0.24

My measured value differs quite a bit from that of Gaia DR2 (0.692″) for this object.

 

A1110AB_JDSO.jpg

Nucleophile(Austin, Texas, USA), form an online thread entitled, 8 Inch Reflector Investigations. Part IV: Bootes, Canes Venatici, Coma Berenices, Ursa Minor, and Virgo

    So much for Newtonians not being suitable for observing high-resolution double stars eh?

    Mr. Hardglass

     

    Sol, that the primary is 8.38″ in diameter is a revelation. I assumed it was the standard 7.9″. When I stow it away for the monsoon, I need to measure it. That’s kind of cool, but definitely non standard for a Newt, yea? I wonder if they are using 8″ SCT blanks that are (supposed to be) a little bit ‘over sized’. Just curious.

    When I do the math for a 2.6mm diagonal support, I get 2.6/8.38 = 31% obstruction. Not a ton of difference, but comforting to some. My MCT has a 30% +/- obstruction and offers no ill feelings. The images are nice. It should have the contrast of a 8.38 – 2.6 = 5.8″ refractor, and you do not hear folks complaining about those views. It still puts ~90% of the maximum light into the Airy disc compared to a perfect 5.8″ APO. It’s right at the diffraction limit with a descent (not premium) mirror.

    Abytec(Pampanga, Philippines), form an online thread entitled: ES Firstlight 8inch dob vs. Skywatcher 8inch dob

    Actually I took lots of measurements regarding the E.S. 8, and measured many times. Not because I was obsessively compelled to, but I had an opportunity to acquire another 8″ mirror with a “pedigree”. So I needed to know if I would be able to use the E.S with little if any modification for an actual 8″ diameter with a traditional 1.4″ thickness to work.

    To the original O.P. the stock E.S. primary is also 7/8″ thick so the 6 point floating cell is just another little plus for the E.S. over the GSO or Synta.

    With the stock E.S. 8 that’s well collimated and cooled Jupiter showed a bit better than TEC140 with really good, (8P) seeing. On D.S.O. no contest.

    Sol Robbins(astronomical author and distinguished sketcher), from an online thread entitled, ES Firstlight 8inch dob vs. Skywatcher 8inch dob

    Hi all,

    Please find attached a drawing of Jupiter I made last night with my 8 inch Newtonian in my home observatory.  I have to say, I was quite impressed with image quality- the details on the disk were easier to see despite the low altitude of the planet.  The main feature was the dark and turbulent SEB(s), and the start of the STropB in the South Tropical Zone.  The EZ was rather active as was the NEB, the NTB and NNTB contained darker sections.  Io is shown in the drawing and was probably the strongest colour I have ever seen, no doubt this is due to the low altitude.

    Best wishes,

    -Paul

     

    Jupiter_2019-06-29-0012UT_visual_PAbel.png

    Paul G. Abel(author, BBC Sky at Night presenter, Leicester, UK), form an online thread entitled: Jupiter and Io last night.

     

     

    From practical experience I have found optical quality, coating quality, proper baffling and eyepiece used more important to contrast than CO size once its below around 30%. Why small APO’s out perform slightly larger obstructed scopes is usually NOT due to being un obstructed but optical quality, mechanical quality and other factors. A smaller CO is nice, but can limit your fully illuminated field and eyepiece choice. Theory is great, but assumes everything is equal which it seldom is.

    The biggest enemy of contrast is scatter, stray light and optical quality if you have a reasonable size CO.

    Richard Whalen(Florida, USA), from an online thread entitled, Secondary Mirror Obstruction?

    TOMDEY, on 02 Apr 2019 – 9:46 PM, said:

    A six-inch scope with a 30% diameter obstruction resolves far better than an unobstructed five-incher. Just generate the non-normalized point-spreads and MTFs to see that in action!

     

    PS: This is why a (good) modest-sized Dobsonian will always blow the socks off a good smaller refractor (any smaller refractor!) for both light-gathering and resolution!

     

    But, gota admit… refractors make fine finder scopes on big Newtonian reflectors…    Tom

    Every time I see yet another thread about secondary mirror sizing and central obstruction (particularly when the MTF graphs start appearing), I say what Tom said above – just use a slightly larger telescope and don’t worry about it.  (And those little refractors do make very nice finder scopes.)

    However, I will also add something else – if you undersize the secondary or size it to only fully illuminate the very center of the field, then you are:

     1) using the part of the secondary that is most likely to have a defect,

     2) using the part of the secondary that might roll off due to cooling,

     3) using the part of the secondary that is often left out of the interferometric analysis, and

     4) forcing yourself into very precise placement of the secondary in order to get something close to a fully and symmetrically illuminated field (in other words, making it very hard on yourself for very little gain).

    My method to size secondaries for most telescopes is simple – add 4″ to half the mirror’s diameter to get the intercept distance.  Then divide by f/#.  Then go up one flat size if the calculation yields a size that is close to a standard flat size.

    So, if I calculate that a 3.1″ or 3.2″ flat is needed, I go to 3.5″.  At 3.4″ – 3.5″, go up to 4.0″.

    The 4″ added to half the mirror’s diameter just allows the use of a filter slide underneath a properly placed SIPS or Paracorr 2.  For a little more breathing room, use 4.5″ in the calculation.

    Try this on various commercial Newtonians and you’ll find that some have secondaries that are too small…..

    Mike Lockwood(premium large aperture mirror maker), from an online thread entitled, Secondary Mirror Obstruction?

    Whew! for my 36-inch F/3.75… that comes out to (18+4)/3.75 = 5.9″ … and mine is 6.25″, with a nice wavefront! And, frankly… even a tad bigger than that might be prudent. I just happened to already have the 6.25 and characterized the wavefront at work… figured a known good one would keep the project hustling along!  I then teased the focuser as close in as possible… reducing that four inches to about three. When I focus my farthest-innie eyepiece… only have a few mm to spare! 

    Tom Dey( retired optical scientist, Springwater, New York, USA), from an online thread entitled, Secondary Mirror Obstruction?

     

    A number of factors are working against reflectors:

    1. Reflectors have central obstructions, which reduce the resolution.There’s also a bit of loss to the spider, which creates diffraction spikes.

    2. Reflectors tend to have problems with temperature differentials within the tube, which creates air currents that distort the image.

    3. Mirrors have more scatter than lenses.

    4. Reflectors have a harder time staying in alignment than refractors.

    5. Reflectors have coma. Refractors have their own problems (chromatic aberration and spherical aberration) but expensive glasses and lens designs can basically eliminate these.

    6. Refractors are usually higher end than reflectors (so, they tend to be higher quality).

    However, you can usually resolve these:

    1, 3. Reflectors scale up far better than refractors, so they can have more aperture, which helps compensate for these problems. Obstruction sizes can be minimized, curved spiders will spread the diffraction spikes around and make them less apparent.

    2. Intelligent fan usage can do a lot for air current formation. Good telescope design can keep cool-down times reasonable and mostly eliminate this issue in use.

    4. It’s pretty easy to get good at reflector collimation. Just keep it collimated.

    5. Coma can be mostly eliminated through use of a paracorr. Or, you can use a longer focal ratio.

    6. There are premium mirror-makers who produce mirrors up to the quality of the best lenses.

    If you resolve these issues, reflectors still do not perform up to the standard of a refractor of the same aperture – but will perform as well as a refractor that is slightly smaller. However, you can get a reflector that is far larger than any refractor you can get. It’s reasonably feasible to get a 12-16″ dobsonian with premium optics and good thermal management, and that will (under good conditions) walk all over any refractor anyone with a normal income will ever be able to afford.

    Mitrovarr(Boise, Idaho, USA), from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    Refractors typically do not suffer from thermals, are typically in excellent collimation, are baffled better, and don’t have a center obstruction.

    The number of reflectors that are miscollimated is astronomical. So overall I think you have a better chance of having a excellent experience with a large APO refractor. BUT, find a 10″ or bigger 1/6th wave or better, perfectly collimated reflector and it will knock your socks off.

    Whichwayisnorth(Southern California, USA), from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    That Dalek, on 03 Mar 2017 – 01:35 AM, said:

    Just a question that came to me. Thanks for any answers!

    Refractors often have better definition, which is the ability to show fine, low-contrast detail.  A reflector solves that problem by being larger, gathering more light and having higher resolution.

    A old rule of thumb is that a 6-inch Newtonian, properly designed and built, will beat a 4-inch refractor.

    Caveman_Astronomer, from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    I will simply say that what we perceive as “sharpness” is not resolution.. A few comments, experiences, thoughts.

    – If I look at 52 Orionis, a 1 arcsecond double star in my 120 mm Orion Eon. It is very close to the Dawes limit so on a perfect night, the disks are overlapping and its difficult split at best. If I point my 10 inch F/5 Dob at 52 Orionis on that same night, and the scope is cooled and of course collimated, 52 Orionis is split wide open. Much smaller disks widely separated.

    In this case, I see 52 Orionis as much sharper in the 10 inch.. But most often, I think the comparisons of both contrast and resolution are made in relative terms, at a 0.5 mm what do I see?

    – Looking at the Globular M79 in Lepus is a 6 inch refractor versus my 22 inch Dob, few would perceive that the refractor was sharper.. M79 in the 22 inch looks about like M13 in a 10 inch. M79 in a 6 inch looks, well we know what it looks like..

    – Reflectors are fininky to the uniniated.. They require care and attention.. Collimation and thermal management are important..

    It always seems there comparisons are made between some sort of ideal refractor and the average faster Newt. An 120 mm F/5 achromats versus a 130 F/5 Newtonian.. I think most would (f)ind the Newtonian sharper…

    Jon Isaac(San Diego, California, USA), from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    mogur, on 04 Mar 2017 – 02:19 AM, said:

     

    dugpatrick, on 03 Mar 2017 – 01:53 AM, said:

    All good points.  But, yes, resolution is better with larger aperture.  An 8″ newt will have better resolution than a 4″ APO. And better CA.

     

    Doug

    Only if it’s PERFECTLY collimated! (a rare find) And I’ll take a little CA over loss of contrast because of a spider vane and secondary obstruction.

     

    Perfect collimation of reflectors is not hard to obtain, with the right tools (Glatter laser + TuBlug or Catseye cheshire + autocollimator).   But not every reflector owner is so demanding of collimation, nor willing to spend for the top-level tools that reliably produce perfect collimation.  OTOH, others of us are a bit happily OCD about collimating our reflectors.

    FirstSight(Raleigh, North Carolina, USA), from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    Apo refractors exist in a sweet spot where their unobstructed aperture and single-pass light path tends to produce better images than similar aperture reflectors in the same seeing conditions. Most amateurs view with seeing conditions that put anything larger than about ten inches at a disadvantage because the scope resolution is limited by the seeing, not the aperture. With steady seeing and constant temperatures (e.g. Florida) reflectors can do just as well as apo refractors for visual use.

    GJJim, from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    mogur, on 04 Mar 2017 – 02:19 AM, said:

     

    dugpatrick, on 03 Mar 2017 – 01:53 AM, said:

    All good points.  But, yes, resolution is better with larger aperture.  An 8″ newt will have better resolution than a 4″ APO. And better CA.

    Only if it’s PERFECTLY collimated! (a rare find) And I’ll take a little CA over loss of contrast because of a spider vane and secondary obstruction.

     

    The difference in inherent resolution between an 8-inch scope and a 4-inch scope is so vast that the Newt would have to have disastrously poor optics or be really badly collimated to flunk this particular test.

    Operating at the magnifications useable in a 4-inch APO, the loss of contrast due to the 8-inch Newt’s central obstruction is barely detectable.

    Tony Flanders(Former Sky&Telescope Editor, Cambridge, MA, USA), from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    osted 04 March 2017 – 08:23 AM

    Mitrovarr, on 04 Mar 2017 – 04:26 AM, said:

     

    grif 678, on 04 Mar 2017 – 03:43 AM, said:

    In all my old books, way back before APO’s and SCT’s. the rule of thumb seemed to be, in all instances, that a 3 inch refractor was about equal to a 6 inch reflector. I often wondered why, since a 6 inch mirror had so much more area than a 3 inch lens, but I guess the focal length and secondary obstruction had something to do with it.

    I wonder if that figure was due to worse coatings back in the day. I really wouldn’t expect a modern 3″ refractor (any kind) to beat a 6″ of equivalent quality. Even back in the day, I’m not sure. I have a really good long 3″ achromat and a good 6″ homemade (not by me) dob, both are at least 30 years old, and the dob totally destroys the refractor on planetary detail.

    I think one only has to setup and RV-6 alongside a 3 inch F/16 achromat to see that even 50 years ago,  a 6 inch Newtonian was far more capable than a 3 inch refractor… 

    Been there,  done that,  know the result,  don’t need to do it again.. 

    Jon Isaac(San Diego, California, USA), from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    We can confidently say that a well-made 4-inch refractor can do better than a well-made 4-inch reflector, but the issue gets a little murkier when we start looking for a refractor that is a serious competitor for a well-made 12-inch Newtonian, for example, or even for a well-made 8-inch Newtonian.

    Caveman_Astronomer, from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    So there I am with my 120 mm F/7.5 Orion Eon with the FLP-53 doublet that cost me $1200 used and next to it is a 10 inch F/5 Dob that cost me $240 used.

    Splitting doubles, the 10 inch does the number on the refractor, viewing Mars, the 10 inch does the number on the refractor. This should be no surprise. This does require an operator who knows how to clean a mirror, the collimate a scope, to cool a scope.. And it does require decent seeing..

    Inch for inch, there is nothing as potent as a small refractor.. Dollar for dollar, pound for pound, reflectors offer more planetary contrast, will split tighter doubles..

    Jon Isaac(San Diego, California, USA), from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    Refractors are great. Too bad they are all so small in aperture

    Caveman_Astronomer, from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    caveman_astronomer, on 04 Mar 2017 – 1:40 PM, said:

     

    Cpk133, on 04 Mar 2017 – 1:25 PM, said:

    God, or natural selection, depending on your persuasion, seems to favor refractive optics for wide fields, low maintenance, and the sharpest views per mm of aperture.

    What kind of refractor should I buy that would compete with a 12-inch Newtonian?

     

    This 10″ refractor should do the trick.  http://www.cloudynig…nch-tec-at-wsp/

     

    $50 000 + $15 000 for the mount and $8 000 for the tripod.

     

    Cotts(Madoc, Ontario, Canada), from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    russell23, on 04 Mar 2017 – 3:24 PM, said:

     

    treadmarks, on 04 Mar 2017 – 3:14 PM, said:

    People often say refractor images are more “aesthetically pleasing” (sharper?) even if they don’t show more detail. Aside from the quality issues mentioned, I’m thinking it’s also because smaller telescopes are more resistant to bad seeing. My understanding of the theory is that larger telescopes can have better contrast through brute-force, by having more clear aperture. So it’s not the contrast giving refractors more aesthetic images, it’s their smallness and the fact that refractors take the most advantage of that smallness.

    That certainly could be part of it.  Another factor for me is the simplicity of the observing.  I am able to sit at the back end of the scope and sight along the tube to locate objects or stars for star hopping.  The viewing is always comfortable like that and sighting along the tube with your eye next to the eyepiece is not as easy with a newt.

     

    Like I said – I’m not ant-Newtonian.  I might even look to pick up a large dob when I retire.  But for now I’m very happy with what I have.

    I think a Newtonian is actually easier to point.  Imagine an object 75 degrees elevation.  With a refractor,  it is very awkward to position my head to look along the tube or through a red Dot or Telrad finder.  With a Newtonian,  the focuser and finders are at the sky end of the scope,  I just lean over,  glance through the Telrad,  point the scope, comfortable and effective. 

    Jon Isaac(San Diego, California, USA) form an online thread entitled, Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    Quote

    I don’t even use a finderscope with my refractor.    The first thing I did when I bought the 120ED was sell the finderscope.     My widest TFOV eyepiece serves as my finderscope.  Sometimes that is the 40mm Pentax XL (2.8 deg TFOV).  Sometimes that is the 32mm plossl, 32mm Brandon or 28mm Pentax XL (1.6 deg TFOV).  Or if I’m feeling really interested in a challenge I might even use the 12mm XF or 9mm Morpheus (0.77 deg TFOV) and go sweeping for the target.    I sight along the tube to locate stars to starhop from or a lot of times I just point the OTA right to the location of the target.   I find it remarkably efficient.

    Like I said,  I can make it work..  You talk about spending more time observing the object,  working a list of double stars at 60 degree elevation with a 50 mm RACI finder is much more efficient than awkwardly sighting along the tube,  and then using a wide field eyepiece to locate the object.. 

    With my short focal length refractors,  I generally just shoot from the hip..  But there is no doubt,  the Dob  with the Telrad and RACI finder is much better for easily finding more challenging objects. 

    Jon Isaac(San Diego, California, USA) form an online thread entitled, Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

     

    Richard Whalen, on 04 Mar 2017 – 6:14 PM, said:

    Planets, brighter DSO objects or the moon in high contrast the refractor can be the best choice.

    After more than 50 years observing, I find the aesthetics of the view more important than the brightness. Also part of the experience for me is also sitting out under the stars on a perfect night and seeing the silhouette of that long white tube against the background of a sky full of stars. Somehow it’s how it should be, and all is right in my world.

    I know what you mean; there’s something about those grand old 6-inch achromats on their massive German equatorial mounts that sends a chill down the spine. The views are incredibly clean, and the scopes are big enough to yield some very detailed views of the planets — but just barely big enough.

    The fact remains that a 12-inch Dob is far cheaper and more portable than a long-focus 6-inch achromat. And while its aesthetics may be lacking, on a good night it can deliver far more planetary detail than said achromat.

    Tony Flanders(Cambridge, MA, USA), form an online thread entitled, Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    mlbex, on 17 Mar 2017 – 6:34 PM, said:

    When is the last time a major observatory built a refractor? As far as I know, the largest refractor still in use is the 36-incher on Mt Hamilton, built in the 1880s (according to Wikipedia)! It’s still a fine telescope, but there’s a reason observatories are building reflectors. Perhaps they scale better. That wouldn’t really be a problem with everyday astronomers.

    Yes, reflectors scale vastly better, for several different reasons. To be precise: false color scales linearly with aperture, large lenses are hard to support, and the glass for a lens has to be perfect throughout its thickness rather than just at the surface. And this is indeed an issue for everyday backyard astronomers.

    Refractors pretty much rule supreme in apertures smaller than 90 mm. There are some pretty good 76-mm Newtonians on the market, but they’re only marginally cheaper than equivalent reflectors, and they have a number of disadvantages. So they appeal mainly to people who are really hard-up for money. There are also a handful of Mak-Cas scopes in apertures of 60 or 70 mm, but since the main benefit of that design is small physical size, and 60- or 70-mm refractors are already quite small, the tiny Mak-Cas’s aren’t very popular.

    Refractors are also quite competitive in apertures from 90 to 125 mm. But toward the top of that range, the disadvantages of the design are beginning to kick in big-time. At 125 mm, either you end up with a short-focus achromat with tons of false color, or a long-focus achromat that’s really unwieldy and hard to mount, or an apochromat that costs a minor fortune.

    At 150 mm, refractors are really a stretch. Very few people can afford apochromats in this size, and with achromats you typically end up with both lots of false color and an unwieldy size. There are nonetheless some people who love 150-mm achromats because of their low light scatter, but that’s truly the end of the line. Refractors bigger than 150 mm (6 inches) are rare indeed in the amateur world.

    With reflective designs, by contrast, you’re just getting started at 150 mm. That’s considered quite small for a Newtonian, and not quite there for an SCT. Eight-inch Newts are really cheap and effective, especially on Dobsonian mounts, and eight inches is the standard size for SCTs.

    In the modern world of amateur astronomy, where deep-sky objects are the most popular targets, even 8 inches isn’t much. That’s barely enough to resolve most globular clusters or see the spiral arms of the biggest and brightest galaxies. So while refractors certainly have their place for viewing wide fields, for viewing the planets in less-than-perfect seeing, and above all for photography, the fact that they scale up poorly definitely limits their popularity among amateur astronomers.

    Tony Flanders(Cambridge, MA, USA), form an online thread entitled, Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    Newtonians, provide a natural, simple viewing position for the eyepiece at all apertures. Refractors and Cassegrains require tall tripods and star diagonals. We’re not going to make the artificial distinction and comparison between 90mm refractors and 90mm reflectors or between any other refractors and reflectors that happen to have nominally matching apertures.

    Caveman_Astronomer, from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    Redbetter, on 20 Mar 2017 – 10:30 AM, said:

     

    caveman_astronomer, on 18 Mar 2017 – 1:17 PM, said:

     

    Newtonians, provide a natural, simple viewing position for the eyepiece at all apertures.

     

    An equatorial Newtonian appears to have some rather unnatural eyepiece positions depending on the declination of the target and the position on relative to the meridian.

    No, I’d say that if an equatorial-mounted Newt has rotating rings, it’s always easy to find some comfortable viewing position regardless of where the scope is pointing.

    However, I don’t really agree that Newts provide the best viewing position regardless of aperture. I do agree that alt-az mounted Newts (including Dobs) have the best ergonomics of all designs up to a focal length of around 1,500 mm, maybe even to 2,000 mm. But beyond that, they start to require increasingly tall ladders, which begin to get genuinely dangerous and/or scary around 3,000 mm. In those focal lengths, I think that Cassegrain designs are quite clearly superior, due to the fact that you’re observing from the bottom of the tube and the fulcrum is closer to the back than the front.

    Refractors certainly have the worst ergonomics, at least in focal lengths above 1,000 mm. They really have the worst of all possible worlds: bottom viewing, long tube, fulcrum far from the eyepiece, viewing angle exacerbates variation in head height rather than counteracting it as with a Newtonian.

    Tony Flanders(Cambridge, MA, USA), form an online thread entitled, Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    I’ve just recently got myself my first refractor (a 120mm f5 achro) after having used an 8″ f6 dob my whole life. I was actually quite surprised to find the ergonomics much worse and I have had to constantly adjust the height of the tripod to find a good position. Despite this, observing close to the horizon for long periods of time seems quite awkward for the neck.

    Olle Erikkson(Sweden), form an online thread entitled, Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    300x in an 8 inch is a 0.7 mm exit pupil or about 37.5x /inch. Even my 70 year old eyes can view the planets at magnification levels and more, provided the seeing supports it.

    I consider 300 x fine for an 8 inch..

    Jon Isaac(San Diego, California, USA),from an online thread entitled, 8″ F/5 Newt planetary and coma

     

     

    Richard Whalen, on 09 Jul 2019 – 04:34 AM, said:

    How much magnification you can use depends on your optical quality, seeing and your eyesight and aperture. With my 8″ scope I am often around 350x to 450x on Jupiter, and 525x on Saturn. Sometimes higher when conditions are perfect.

     

    My rule of thumb is 43x the aperture in inches on a very good night with decent optics, higher for very good or excellent optics. Also much depends on which planet you are observing.

    Richard, I am usually between 333x and 400x on Jupiter in my 8″, as well, at 0.6mm and 0.5mm exit pupil. I find 333x (~40x per inch) power to be the most productive and my rule of thumb, as well. At 400x, Jupiter is still workable, but it’s beginning to dim a little. I was looking at Oval BA the other night, it was easy at 333x. I could see it at 400x, but not as easily.  And I am fairly sure at 500x it would have been even more difficult. I accidentally pulled out the wrong eyepiece and hit 1200x once (0.16mm exit pupil!). Not much to see up that high. I guess my optics are not that good. smile.gif

    I get that the quality of our optics produce nice sharp and high contrast images at high power, after all it’s the same quality image we see at less magnification where (lack of) aberration is apparent in terms of resolution and contrast. But I am always interested in the mechanism of how high quality optics can afford higher magnifications at vanishingly small exit pupils, say a bit smaller than 0.5mm, without excessive image dimming. At some point we begin to lose visual sensitivity and, thus, lose the image itself as the eye is working at a very small relative aperture (less than about 0.5mm f/60).

    Getting closer to 600x on Jupiter, IME, is unworkable (or at least not as productive as a bit less magnification) in any 8″ aperture even in good seeing. I mean, we can still see some detail up that high, I saw some detail at 1200x, too. Just not much detail was perceived by the eye, even though we are viewing the same fine afocal image we observed at 400x and less. At some point, it becomes less about the optics and more about the exit pupil and, I suspect, throughput as well.

    For example, Jove is fine on both 6″ Mak and 8″ Newt at 0.6mm exit pupil, (240x and 333x, respectively). But, at 0.5mm exit pupil, the Mak image is unworkable while the Newt image still had some legs. I suspect this has something to do with the throughput of each scope, not so much about their respective quality or difference in aperture. Of course the 8″ image is brighter, thus affording higher magnification than the 6″. They are pretty close to the same level of quality, not premium but pretty good and roughly the same obstruction. Both were thermally stable and well collimated. Seeing varied from above average to very good in both over time.  (I agree with you in another thread when you talked about stray light control and mechanics, too.) 

    But, when I hear folks talk about quality optics affording higher magnification, I am always reminded of the small exit pupil involved and how quality might over come the inverse square law and our own personal level of acuity (as a variable). Unless you or they mean magnification higher than say 1mm exit pupil when poor optics start to become visually and visibly soft, while better optics retain their fine imaging properties until the image surface brightness is no longer supported at smaller exit pupils. Sometimes when folks talk about ludicrous magnification in any scope, and especially in premium scopes, I wish they’d elaborate on what they saw up that high. Tight double stars or a bright planetary nebula? 

    I just do not understand how quality affords higher magnification to smaller than 0.5mm exit pupils (very small relative apertures) and well above the magnification where poor image quality becomes apparent. 

    Asbytec(Pampanga, Philippines), from an online thread entitled, 8″ F/5 Newt planetary and coma

    After 500x the image starts to get too dim in a 8″. This is where a 14.5″ shows it’s stuff at 1000x on Jupiter.

    Chas, I know you have great seeing. My seeing is pretty much the same during our dry season monsoon. So, yea, we’re operating at higher magnifications, generally, and on Jupiter, specifically, as well as other objects. I guess that is the crux of my question. Assuming descent optics in both, the 14.5′ at 1000x is about the same as an 8″ near 550x. In my experience with an 8″, the image is less productive starting about 400x and above. Others may vary somewhat, of course.

    Unless the optics are truly better in the 14.5″ in appropriately good seeing. Then my question is why can the higher quality, larger 14.5″ aperture show it’s stuff at much higher magnification than roughly the equivelent of an 8″ showing it’s stuff at 400x? The equivelent magnification in the 14.5″ would be about 750x, but why does quality allow it to show it’s stuff at 1000x (equivelent of 550x in the 8″)? I’d love to know what can be seen up that high because, my thoughts are, the 14.5″ image is dimming, too, for the same reason the 8″ is already dimming at 400x and higher.

    I’ve seen the Jovian image at 500x and 600x in the 8″, but I would not call it really a great image (on the eye, anyway). There is some detail to be seen, still, and the limb appears to be as sharp. But, a lot of the lower contrast detail is becoming or is already difficult to see. Bright high contrast stuff like double stars are no problem, but Jove is a different animal. It cannot be pushed to ludicrous magnifications, but if it can and optics are the reason, then my question is why and what is seen up that high. A sharp limb, a few belts, the moons, and maybe the GRS?

    Asbytec(Pampanga, Philippines), from an online thread entitled, 8″ F/5 Newt planetary and coma

    My lifetime-best view of Jupiter in the 12.5″ was at 456x (36.5x/inch), and we could see a knotty white swirl in the salmon colored (then, now it’s more orange) GRS.

    The whole disc looked like the surface of an orb, not a flat disc, and the colors were amazing–ochers, pale ivory, bluish tints, grey-greens, reds, whites, blacks, greys, etc.

    It was a technicolor image, and super-sharp–sharp enough we could see the shadows of projections on the cloud banks below. And an 18 element stack of lenses in the focuser.

    Spectacular seeing conditions, obviously.

    On other nights of superb seeing, I’ve gone as high as 986x (79x/inch), just to see if it could be done, but I haven’t been able to see what I saw that night.

    The moral of the story is that it is not only optical quality, but seeing that determines how high a magnification we can use.

    In absolutely perfect seeing, I’ve used a superb 7″ scope at 160x/inch and the image was OK. I just couldn’t see anything in that scope at 160x/inch

    that I couldn’t also see at 100x/inch, though the image of Saturn at 1123x was incredibly large.

    But even after all the crazy high powers, give me 400-500x with spectacular seeing, and I can see details on Ganymede and Neptune. 1000x isn’t really necessary.

    It’s all about the seeing.

    Starman1(Los Angeles, California, USA), from an online thread entitled, 8″ F/5 Newt planetary and coma

     

    The short answer is that a good Premium telescope will probably perform noticeably better than an average cheap mass-marketed one. Somewhere between better and way better. But that’s actually a statistical statement. Occasionally a too-good-performing cheap one somehow slips through their QC system… and occasionally a Premium scope will be deficient. The Premium scope is almost always worth the Premium price differential. That is to say — if you don’t want to mess around — just buy the better scope and enjoy it! 

    Tom Dey(Springwater, New York, USA), from an online thread entitled: Premium 1/10PV 8″ Newtonian vs mass market 8″ Newtonian.

    I owned a Synta 8”f6 Dob along with a custom 8”f6 Dob with a Zambuto mirror for several years. The differences in the views were subtle, requiring side-by-side viewing on rare nights of excellent seeing to confirm. On the other hand, the improvements in the views offered by two inches additional inches of inexpensive aperture were obvious.

    If an 8” scope is the largest you want to handle, and you want improved views, premium 8” optics will provide a marginal improvement at about 10x the cost. An inexpensive 10” scope will cost about 2x and the improvements in its views will be obvious. However, premium scopes usually come with premium mechanics in addition to premium optics, and the mechanical improvements are usually obvious under all circumstances.

    So, my preferred approach these days is to empirically determine the largest scope that I am comfortable using at an observing site, and then upgrade or replace its optics and mechanics as much as my budget allows

    Gwlee, from an online thread entitled: Premium 1/10PV 8″ Newtonian vs mass market 8″ Newtonian.

    Make sure that “1/10 wave Peak-to-Valley” rating is on the wavefront, not the mirror surface. Also, make sure the seller has a good reputation.

    I went a different route, and had my first Synta 8″ F/6 mirror re-ground by a respected glass-pusher, as its initial figure was quite poor. To fill in the gap while this was in process, I purchased a second Synta 8″ F/6 (yeah, seems like a stupid idea, but the second one was reasonably good). The total cost was lower than buying a complete specialist-built scope, but of course I had to do a little work myself.

    I’ve decided to hold onto both scopes for now. I’ve set up the one with the great mirror using a better mirror cell, low-profile focuser, and smaller secondary, optimizing it for high magnifications, while the second scope is for lower mags, with a larger fully-illuminated field.

    Like you, an 8″ Newtonian is at my limit for weight and size.

    Hoawardcano(Olathe, Kansas, USA), from an online thread entitled: Premium 1/10PV 8″ Newtonian vs mass market 8″ Newtonian.

    Starlease, on 19 Jul 2019 – 7:44 PM, said:

    Put a Zambuto mirror in my 10″ dob and it outperformed my 14″ claimed 1/8 wave dob for planetary details seen. Little tiny details on Mars seen in 10″ were invisible in 14″.

    Your 14″ dob at 1/8 wave is about 1/4 wave at the wavefront – just diffraction limited. It’s possible in extremely good seeing that your 10″ would show more detail, but on an average night I doubt it, unless there are other issues that you haven’t thought about like cooldown, collimation, mounting of optical components, or maybe the claim of diffraction limited of the 14″ isn’t true.

    People are always looking for fairy dust they can sprinkle into their telescopes to make them defy the laws of physics. Someone let me know if it works. smile.gif

    Nirvanix(Medicine Hat, Alberta, Canada), from an online thread entitled: Premium 1/10PV 8″ Newtonian vs mass market 8″ Newtonian.

    Replacing the 2ndry will probably be the best bet

    but you should learn how to star test 

    https://youtu.be/QxUQJjjsdW4

    Pinbout(Montclair, New Jersey, USA), from an online thread entitled: Premium 1/10PV 8″ Newtonian vs mass market 8″ Newtonian.

    Although I didn’t do it with 8″, but with 10″, I think the mirror exchange was a large improvement for visual observations. Views through my GSO 10″ were good, but star tests have shown some astigmatism. Following the advice on this forum, I exchanged the secondary mirror for Antares, but the astigmatism was still there. So, I decided to exchange the primary for the 1/10 pv. The difference is considerable. With GSO mirror, the views were very good, now they are great. I can see many more crispy details on Jupiter, Saturn, Mars or the Moon. Things that were ‘soft’ before are sharper now. And it happens even on the nights with poorer seeing, I just have to wait for the moment in between smile.gif

    For low-power, wide-field DS objects, probably there is no difference, but color: GSO coating produced a greenish touch, OOUK makes it more white/ flat.

    With GSO mirror, I often used the aperture mask to see planets sharper. After exchange, in my opinion the aperture mask only makes things dimmer and less sharp, so I guess the scatter light before was bigger with the standard mirror. 

    Overall, I have learnt the lesson saying that the exchange for a better mirror was worth it, the telescope is used now more often for the sheer joy of visual hunt for details.

    WOJ2007(Tychy, Poland), from an online thread entitled: Premium 1/10PV 8″ Newtonian vs mass market 8″ Newtonian.

    After owning a really fine 8” CZ mirror for several years I am always impressed by the views when the mirrors are properly collimated and when the primary mirror has reached thermal equilibrium. Is it better than a mass market 8”? I can’t say because I have no way to compare. It’s also really light for the given aperture (better construction/thinner mirror) without giving up stability.

    What I can say about my premium reflector is that the mechanicals beat the pants off my venerable, but flawed 10”. The focuser, balance, bearing smoothness, primary mirror cell, secondary mirror holder are superior in every way. The entire tube is flocked and the cradle design allows the tube to be easily turned and/or moved north south. My definition of a premium scope (which includes the mirror) is one that both offers expected mirror performance while the structure disappears as one uses it. A premium scope is more than a premium mirror and a premium mirror will fall short of full potential if one has to battle with the other parts.

    Chesterguy(Stillwater, Oklahoma, USA) from an online thread entitled: Premium 1/10PV 8″ Newtonian vs mass market 8″ Newtonian.

    I have two 8ers to compare, one Zambuto 8″ F7, the other a generic “Skywatcher” 8″ F6.

    But the comparison is necessarily through memory . . .

    I visit family a couple of times per year in Australia. Got tired of lugging my C6 and refractor through airports. So last time back I bought an 8″ F6 “Saxon”, which is the same as the Skywatcher 8″ solid tube.

    About a year ago I came across an ad where a guy had the parts for an 8″ F7–the primary being a Zambuto quartz, and the secondary a 1/30 wave Antares. Moonlight single-speed focuser. A solid tube (flocked), and splashed out for an Aurora precision cell. I run it alt-az on a Skytee 2 mount.

    How do they compare?

    I wasn’t expecting miracles with the Saxon. A solid diffraction limited scope was all I was wanting.

    First object was Sirius at high elevation in quite good seeing. Within 2 minutes of setting up the scope on first light I easily split the pup. Done. This is a good scope!

    Star test isn’t perfect (I am no expert on this). My recollection was a brighter ring on the outside on one side or the other of focus. So I’m guessing a less than perfect edge. But it performs very well indeed, and more than met my hopes. I haven’t spend much time on planets with this scope (it does perfectly fine). When down under I’m more interested in the Southern objects–Magellanic clouds put up a ton of detail in this scope.

    But what about that Zambuto? Well, as far as I can tell it is as close to perfect as you can get in an 8″ mirror. Star test looks identical to my eye on either side of focus.

    The mirror is up and ready to go with just a couple minutes of running a fan, and puts up etched views of the planets and moon (it has a very small secondary, and is optimized for planets). A particularly memorable view was of the double double from Mt Pinos (parking lot must be close to 8k ft). Perfect dots and diffraction rings. An observing friend with a lot of experience called it the best view of the double double he’d ever seen.

    But how would this thing compare to a 10″. Well, I think you’ll get a more sharp/contrasty view out of the 8″ premium, but so long as the 10″ is decent, it will resolve more detail, those details will just look a tad softer.

    Areyoukiddingme, from an online thread entitled: Premium 1/10PV 8″ Newtonian vs mass market 8″ Newtonian.

    N3p, on 19 Jul 2019 – 5:57 PM, said:

    Has anyone replaced their regular 8″ Synta Newtonian with a higher quality 8″ Newtonian and how was your experience?

    The key difference I found was as follows.    During critical observation of an object for 5-10 mins, on the couple of times when the atmospheric seeing snapped into focus- lasting 0.5 to 2 seconds- the mass market mirror would give an “ooh nice” response whereas the premium would give a “wow!” response.

    The rest of the time the mirrors were pretty similar.

    On galaxies, the higher strehl mirror gave just enough contrast to pass a threshold where the eye could suddenly detect a dust lane.   The mass market mirror couldn’t reach that threshold.

    Max T, from an online thread entitled, Premium 1/10PV 8″ Newtonian vs mass market 8″ Newtonian.

     

    An inspiring 6″ f/8 ATM build by Matthew Paul, Orange County, New York, USA

    Though I did not  build the scope for imaging, I wanted to share what it is capable of under not so ideal conditions. Very happy with the results of the optics. I need to build a better OTA for it. It’s rather flimsy, the spider is not rigid, the tube flexes, and the focuser is just a plastic rack and pinion, but it works very well for now, and the hard part (the optics) are done. Thank you again to everyone that offered information and assistance as I worked on the mirror.

    MVI_0140-3.jpg

    Matthew Paul(Orange County, New York, USA) quoted here

    Matthew Paul, on 22 Jul 2019 – 3:32 PM, said:

    Though I did not  build the scope for imaging, I wanted to share what it is capable of under not so ideal conditions. Very happy with the results of the optics. I need to build a better OTA for it. It’s rather flimsy, the spider is not rigid, the tube flexes, and the focuser is just a plastic rack and pinion, but it works very well for now, and the hard part (the optics) are done. Thank you again to everyone that offered information and assistance as I worked on the mirror.

    attachicon.gif MVI_0140-3.jpg

    That image ought to give apo owners pause.

    Ed Turco(Lincoln, Rhode Island, USA), from the same thread

    There is real poetic justice in how well a good Newtonian telescope performs.

    JamesMStephens(Hattiesburg, Mississippi, USA), from the same thread.

     

    Hello Marty, I can’t answer all your questions, but I did a shoot out between a 150mm f/8 achor and 200mm f/6 dob on Mars a few years ago at opposition.

    The Dob was much better, I suspect it had more to do with no CA vs the increase in aperture. Mars was smeared with false color rendering very little detail in the views. I sold the Achro because it was too much for me to mount. And in my light polluted sky, I don’t do much low power deep sky.

    I suspect that It would also lose fine detail on Jupiter, but I could not do a side by side compare.

    I have a 6 inch 150 f/5 newt, and it does a good job on Juipter/Saturn. I have not had a shoot out between it and say a 100mm ED, or 120 8.3 acrho for a comparison. As far as personal tastes, my eyes are getting old and are light starved, so usually a brighter less crisp image is preferred over a dimmer crisper one.

    I suspect …. the best scope for viewing the planets at 150mm without going crazy expensive would be the 150 f/8 dob. I’m looking for one right now in the used market. A 120 ed I suspect would do a good job too, but at 4x the price, and a big mount to boot.

    I have an f/5 250 reflector on a dob mount. Best view of Jupiter I have. It does take an hour to cool.

    Vtornado( Northern Illinois, USA), from an online thread entitled: 150mm Instrument for Planets, Which Type?

    I’ve tried them all over the past 40 years.  Best view of planets was through Newts with good mirrors that were properly collimated. Note the underline, because that (particularly the latter) can be an issue with Newts. For something more compact and lightweight a good 6″ Mak is an excellent planetary scope and it won’t cost you an arm and leg.  I just picked up a used Orion 150 Mak and the (visual) images of Jupiter and Saturn are superb. My old 127 Mak is also good but the 150 gives more edge on brightness.

    fcathell(Tucson, Arizona, USA), from an online thread entitled: 150mm Instrument for Planets, Which Type?

    I think a 6” f/8 dob, with top notch optics

    (Spooner) would be a great choice and affordable.

    NHRob, from an online thread entitled: 150mm Instrument for Planets, Which Type?

    6″ mak

    6″ f/8 newt

    4″ fpl-53 double Vixen or triple

    will all give great planet views.

    tomjones, from an online thread entitled: 150mm Instrument for Planets, Which Type?

    tomjones, on 23 Aug 2019 – 01:02 AM, said:

    6″ mak

    6″ f/8 newt

    4″ fpl-53 double Vixen or triple

    will all give great planet views.

    Why add a 4″ into this discussion when it’s an inferior option?  A good 6″ f8 outdoes it.

    azure1961p, from an online thread entitled: 150mm Instrument for Planets, Which Type?

    MalVeauX, on 23 Aug 2019 – 6:33 PM, said:

    So… to add more to this mix…

     

    What would any experienced observers rate a 200mm F6 Quartz reflector to a 150mm F8 ED doublet for planetary views?

     

    Would the extra aperture make enough of a difference?
    Or would the 150mm F8 ED refractor still throw up the better, higher contrast image?

     

    Very best,

    The extra aperture would make enough of a difference if the mirror were superb, the tube material, thermal issues, focuser etc., were all finely tuned and working together. Then there are the ergonomics of viewing position and the question of what type of mount will be used.

    If one were to buy a used 8″ f/6 “classic” EQ mounted Newtonian from a good source, such as someone here on CN, then that would be a very efficient bang for the buck. Especially if the mirror were a known and proven winner. Probably in the Approximately $500 range vs. $2000 for the 150mm f/8 ED.

    “Would the 150mm F8 ED refractor still throw up the better, higher contrast image?” Yes it could, if the 8″ f/6 newt had degraded mirror coating and dust, not collimated perfectly, focuser not smooth, set up on warm surface so that thermals enter the tube and plague the system etc., But in my opinion the Newtonian will win if the details are all taken care of and watched. 

    I wish I could find a local old classic 8″ F/6 EQ mounted Newt to play around with, actually…

    Everlasting Sky( Vancouver, Canada), from an online thread entitled: 150mm Instrument for Planets, Which Type?

    I concur with fcathell, as far as planetary observing with Newtonians when all the necessary conditions are in play. My very best planetary views have been through large truss-tube Dobsonians with premium mirrors, along with large classical Cassegrains, when the seeing has been excellent.

    I also agree with Richard Whalen’s post when the aperture is limited to 6 inches.

    Dave Mitsky(PA, USA), from an online thread entitled: 150mm Instrument for Planets, Which Type?

    Quote

    Even with spot on collimation (Newts, DOBs, Maks, SCT’s, etc.) – you still have a central obstruction vs. none in a refractor and that reduces contrast and resolution…even if just slightly — it does

    It’s worth keeping in mind that the CO does have a small effect on contrast, not on resolution..

    This does mean that a scope without an obstruction, when compared to an other equivalent scope of equal aperture will have reduced fine scale contrast.

    But that’s only if the apertures are identical and the optical quality similar. Otherwise, the contrast is affected by the aperture far more than by a central obstruction. This is why large scopes with COs can provide much greater contrast than a scope without a CO.

    Some years ago I experimented with my 120 Eon by adding a 40% CO, I could see a loss of contrast but it was surprisingly small.

    In this comparison, unless one went with a high quality Newtonians (Spooner) then a $2500 ED Doublet would likely provide better planetary views.

    On the other hand, if weight and length were the guidelines, the a good 8 inch Newt would be hard to beat.

    Jon Isaac( San Diego, California, USA), from an online thread entitled: 150mm Instrument for Planets, Which Type?

    M11Mike, on 24 Aug 2019 – 01:12 AM, said:

    Jon – normally I’m with you 99.9%.  But I have seen numerous times FIRST HAND where a quality 4″ refractor beat out much larger apertures on the planets.  And I don’t think the guys with these scopes didn’t have them properly collimated, etc.  These guys with scopes (like the Meade 10″ SCT) were my observing buddies and they concurred.   They were active seasoned observers like myself.

     

    Mike

     

    Well.. maybe. But you can’t blame that on the CO.  Thermal issues, optical issues, poor seeing..

    Try adding a 35% CO to a 4 inch Refractor and see how much difference it makes.

    Jon Isaac( San Diego, California, USA), from an online thread entitled: 150mm Instrument for Planets, Which Type?

    I’ve had a 6″ F8 newt with 1/8 wave optics and it was excellent for L&P. I’ve got a IM715D mak and the same can be said of it. Big advantage to the mak is in 8 years I’ve never had to collimate it. Either scope would work on my Twilight 2 without a counterweight, I doubt the same could be said of a 6″ refractor. I’ve got an excellent WO ZS110 triplet and it doesn’t outperform my mak or C9.25XLT for L&P unless seeings sub par.

    dscarpa(San Diego, California, USA), from an online thread entitled: 150mm Instrument for Planets, Which Type?

    First Light Report
    Finally, the time had come for first light.  When I put the Glatter laser collimator into the focuser and turned it on to begin aligning the optics, I was stunned to see that the laser beam was hitting the primary mirror inside the circle in the middle of the hotspot.  Despite being driven over 1000 miles and loaded/unloaded twice, the tolerances are tight enough on the telescope. I’ve setup the telescope four different times since – and the initial laser position on the mirror has been inside the 1/4″ (6 mm) hole at the center of the HotSpot every time.  Collimation required less than 1/16 of revolution of any of the knobs on either the secondary or primary mirrors.  I pointed the telescope at the horizon and the zenith.  I moved quickly in altitude and azimuth, and slid the EQ platform through it’s entire range of motion twice.  Collimation didn’t shift.  At all.  
     
    Once the sun dove behind the hills just to the west of the observing site, I uncovered the optics and started the fan in earnest to get the optics cooled to ambient as quickly as possible.  I carry a 10″ rechargeable fan that I used to push air at the front side of the primary mirror, and allowed the built in fan to pull air across the back.  The mirror box is only about 8″ deep in total, so air is able to flow easily around the optics and through the structure to help with temperature changes and cooling. Once full darkness had descended up on the observing site, I removed the front fan, rechecked collimation and got to the business of deep sky observing with the new telescope.  I left the rear fan running at full speed, where it’s just audible as a background noise.  Later I turned this down some just to quiet the fan in the silent nighttime desert. Temperatures dropped 23º F (12º C) over the next 2 hours. The thin optics and open structure of the observing rig did a wonderful job of keeping up with the change.  
     
    When I first began talking with Mike Lockwood about commissioning a fast, thin mirror he told me that I’d likely never seen what a cooled telescope could really do being that my main observing machine has been a 15″ full thickness OMI mirror in a wooden Obsession structure.  I love that telescope, but I learned on this weekend what Mike was talking about.  Conditions that had been blamed for years on poor seeing were not present on this night, even though we all agreed that the seeing wasn’t any better or worse than a typical night at this location.  I spent nearly all of my time over the next few nights observing comfortably with much higher magnifications than I’d ever been able to use previously. 
     
    NGC 5139 – Even though it culminates at just 11º above our southern horizon, Omega Centauri was on the meridian at the end of astronomical twilight, so the three of us agreed that it was the obvious choice for the first target.  We’re all familiar with the views of this object from this site with instruments of all sizes from a 63mm Zeiss refractor to a 20″ f/5 Obsession.  At this low elevation there were some obvious atmospheric artifacts being induced in the image – but we all agreed that this was the finest view we’d had of this granddaddy of globulars.  With a 21mm Ethos I immediately noticed a couple of things.  1 – The telescope maintained perfect balance though it was pointed 10º above the horizon.  When I removed the eyepiece to switch to a lighter one, the telescope didn’t budge.  I’m no designer, but I attribute this to the use of the 30″ altitude bearings and perfectly balanced design.  2 – I was looking at Omega Centauri with 20″ of aperture and a 1.2º true field of view.  The cluster was lost in the middle of a field with all kinds of black space around it. With all that aperture focusing all that globular into the smaller image scale of this wide field, the cluster was astonishingly bright, even by it’s elevated standards.  I hadn’t changed eyepieces or objects yet, and I already knew…..this was going to be a fun telescope.  At 175x in a 10mm Ethos, the cluster is huge, extending nearly to the edges of the field.  What I noticed most was the stars being impossibly tight pinpoints, with black space around them.  The contrast between the globular’s stars and the background sky is the most notable thing from the observation.  
     
    NGC 5128 – This beauty in Centaurus is so close by that you can’t *not* look at it.  Again, the contrast was the most noticeable thing about the observation.  With the 10mm Ethos, the dust lane is sharp and well defined across the face of the galaxy and appears nearly bi-sected with a brighter middle – like looking at the great rift from millions of light years away.  
     
    I wiled away a few hours working through the Virgo cluster high in the west, spent some time counting galaxies in the Coma cluster and then happened upon what has been the most memorable view through this telescope yet.  
     
    M83 – Again, it was the contrast.  An absolute pinpoint of a nucleus with two sharply defined bars extending away for a few arc minutes and then turning sharply to form those beautiful, elegant spiral arms.  What struck me most though was the dark lanes between the arms.  As I continued observing, differences in darkness began to appear in the dark lanes, as well as brighter spots in the spiral arms (HII, OB assocations?).  I didn’t concern myself too much, I just enjoyed the view.  This telescope rocketed this galaxy to a high place on my favorite objects list.  
     
    M57 – I put the telescope on this old standby and basically went camping at the eyepiece.  With an 8mm Ethos, the central star was just there.  It didn’t jump out at you….but it was there and required no effort beyond basic averted vision to see it clearly.  I noted galaxy IC 1296 nearby and that it too was pretty easily seen.  This was where I pushed the magnification.  With a 3.7mm Ethos, the telescope is operating at 475x magnification.  In moments where the seeing settled and the air was steady, the optics weren’t even breaking a sweat.  I was able to observe 4 stars seemingly involved with the nebulosity and the central star was a direct vision object at this magnification.  The interior surfaces of the nebula were clearly mottled and uneven and the entire nebula appeard electric green in the eyepiece.  
     
    Veil Nebula – Always a favorite, our small group spent a solid hour cruising the wisps of this supernova remnant with the telescope.  With an 8mm Ethos and an O-III filter, the nebulosity glows as if backlit by some artificial LED source in the eyepiece.  I traced the entire outline of the nebula noting how the brighter wisps faded into thinner and fainter ones as I followed until they just seemed to disappear.  There’s a patchwork background of nebulosity that I hadn’t noticed before with my 15″ scope.  

    48370580567_bd2a867e80_c.jpg
    Great friend and fellow observer Alan Strauss told me I needed to remain still while observing M101.  Uhhhhh….okay!  That won’t be hard.  I could sit here all night.  
     
    …and then came the planets.  I have listened to Mike Lockwood bang the drum about planetary observing with big aperture mirrors for quite awhile now.  Like I told him afterward, consider me one of the converted.  Jupiter at any magnification was an absolute razor blade of sharpness.  Where I was used to seeing equatorial bands, I was now greeted with a swirling mess of sharply defined festoons and bands within bands.  Viewing Jupiter this night was the best views I’ve had that I can ever remember.  My friend Alan commented a few weeks later that the thing that stood out most to him was how sharp the planetary views were through this 20″ scope – he wasn’t expecting it to perform the way that it did.  I concur.  
     
    Just a couple of weeks ago, I set the telescope up again in my light polluted Phoenix backyard to give a quick view of the moon and Jupiter to my lady.  I’ve not been much of a lunar observer since I was a kid, but she is in love with the moon….so, it was time to show her the moon through the new telescope.  She’s not an astronomer by any means….and she’ll be the first to tell you that she doesn’t have those aspirations.  I was stupefied when I looked in the eyepiece.  Stop me if you’ve heard this before – the contrast is unbelievable  – and not just the inky blackness of the crater shadows and brightness of sunlit portions of the lunar surface.  The subtle variations in illumination in the mare and even light differences in color were obvious and a pleasure to behold.  What was supposed to be a quick 20 minute show of the moon and Jupiter turned in to a 2.5 hour session together.  We spent the longest time comparing notes and pointing out features and seeing the smallest details.  The experience has converted me into someone who’s ready to look at the moon again.  I look forward to the intersection of my travel schedule with a break in the Arizona monsoon and a favorable location of the moon so I can repeat the experience.  
     
    Conclusion
    I wanted big aperture with no ladder and absolutely no compromises on the optical and structural quality of the telescope.  It came with an uncompromising price tag too – but I couldn’t be happier with the combination of the Lockwood optics and Osypowski structure & platform.  Mike Lockwood’s reputation for ridiculously fast, sharp optics is well deserved and I’d even dare say still underappreciated.  I selected Mike as my optician for a couple of reasons.  1 – He was great to talk too and has been a great resource for all astronomy/telescope related questions since first talking with him back in December 2017.  2 – A couple of extremely experienced observers that I respect greatly both said the same thing – that the best view that they’d ever had through a telescope had Lockwood optics.  I can now say I wholeheartedly agree with their assessment. 
     
    The Spica Eyes structure built by Tom Osypowski is as nearly perfect as I think it’s possible to build at this point.  It is substantial, stiff and rigid.  It feels like it’s been built for the apocalypse when you put your hands on it.  I chose Tom because of my experience with his EQ platforms and the knowledge that he’s built several telescopes that were both larger *and* faster than this project – so I was confident i would get a telescope that matched my excitement for the EQ platform.  I haven’t been disappointed.  Twice now I’ve done business with Tom.  Both transactions rank as the smoothest, most pleasant money I’ve spent in this pursuit in my lifetime.  I’m proud to be able to say I own one of his telescopes.  
     
    Is the telescope truly perfect?  No.  I have two minor quibbles.

    • There is some stiction in the azimuth axis.  It’s not paralyzing, but it is there.  I got after it when I got back home with some car wax and a buffing cloth which has improved it.  Part of this issue is comparing it to the buttery smooth goodness that is the motion of an Obsession.  I’ve been spoiled by 18 years of use with my 15″ Classic.  
    • The light shroud fits really, really tight.  Getting it pulled down over the structure is a bit of a process.  By process, I mean it takes a couple of minutes.  Once it’s in place – it stays in place and does a wonderful job of blocking stray light but still allowing airflow through it.  So I’ll count my blessings that these are my issues with the telescope.

    I realize it’s been long winded, but there’s little information out there about Spica Eyes scopes.  In fact, there’s really not much beyond a different CN thread that was posted a few years ago about a 24″ scope Tom built.  I submit this review and future experiences and observing reports as part of that body of knowledge.  Tom Osypowski tends to fly under the radar when discussing premium telescope builders, but his handiwork is among the absolute best out there.  He and Mike Lockwood have earned every bit of credit that they get for their skills and contributions to our hobby. 
     
    Mike

    48260256751_f91f413582_c.jpg
    A great shot of the observing site in Portal, Arizona, the 20″ f/3 telescope described here, and the truck/camper that gives me shelter whilst far from civilization for long periods of time.  The light domes are greatly exaggerated in this long exposure.  The one just to the left of the truck is from Lordsburg, NM – 40 miles (64 km) away.  The light dome to the right is from El Paso, TX – 160 miles (255 km) away.

    Mike Wiles( Phoenix, Arizona, USA), from an online thread entitled, First Light Report: 20″ f/3 Spica Eyes/Lockwood Dobsonian

     

    Recently picked up a used (mint condition) Skywatcher 130mm f/5 PDS reflector OTA (Thanks Tyson). This scope is presently discontinued.

    Cosmetics: beautiful black with silver speckles. 9/10

    Inclusions: 8/10 (based on the nice focuser)

    excellent dual rate 2” Crayford focuser with 1.25” adapter

    Vixen style finder mounting shoe

    thin 4 vein spider/ adjustable 2° mirror holder

    oversized 2° mirror (this scope is designed for photography)

    Enhanced 95% coatings on 1° and 2° mirrors

    6×30 straight through finder (mine was upgraded to an Orion 8×40 straight through version)

    2” 28mm LET eyepiece (not included in my used purchase)

    Nice dual hinged mounting rings and Vixen style mounting 7” bar

    Peeves:

    Crayford focuser is non-compression ring

    Crayford focuser has a thread 2” adapter ring using a single metal set screw

    (I removed the ring and drilled/tapped 3 holes a 120° and replaced the metal set screw with 3 nylon ones). I actually prefer this type with nylon screws to a compression ring version.

    the 2”-1.25” eyepiece adapter is also thread-on. You need to unthread the 2” eyepiece adapter ring and the thread the 2”-1.25” one on. Stupid design, just include a regular 2”-1.25” – compression ring or set screw.

    You need a 2” extension tube to reach focus with either 2” or 1.25”, It is not included.

    The included 28mm 2” LET eyepiece is junk (I have tried one). Just include a 1.25” cheapo 25mm Plossl eyepiece.

    I hate straight through finder scopes, replaced mine with an Orion 6×30 RACI version (very light weight but a larger 50mm RACI maybe a better option.

    Optics: 10/10

    easily collimation (it arrived in perfect collimation), 1° mirror is center spotted

    3 spring loaded adjustment knobs with setscrew locks

    95% enhanced 1°/2° mirrors – brighter view than my larger 140mm f/3.64 Comet Catcher

    optical testing – easily 1/8 wave or better

    Observing: I am mainly a Deepsky observer – this a definite RFT

    Fantastic scope, easily punches above a 5” reflector.

    easily takes 160X + (TV 4mm DeLite) , 40x/in- you run out of light grasp

    From low power wide field (3° +) to high power, does it all.

    with high quality eyepieces, I did not need an OCS (Paracorr)

    Some Deep Sky highlights: NELM 5.7 Transparency/Seeing Both 3/5 :

    the Double Cluster – superb, one of my best views ever (mono view)

    NGC 7789 in Cassiopeia (Caroline’s Haystack) – very easy (large smudge with a sprinkling of brighter stars)

    M31 group – all 3 members are easy with direct vision – M31 over 2.25°, M110 diffuse oval

    M33 – large 3/4° smudge

    M81/82 – beautiful contrast in galaxy types

    M51 – Both parts easily visible

    M13 – easily resolved – perfect image (pin **** stars) at 160x

    M27 – amazing with and without filters

    NGC 7000 – fantastic North American shape with NPB filter

    Veil Complex – see my posting in Observing section (Veil in small scopes)

    Future Upgrades:

    I have added a 8” dew-shield

    I will flock the OTA (either the entire tube or opposite the focuser)

    Summary:

    An excellent low priced RFT. Amazing Optics.

    The few minor “peeves” are easily corrected.

    Highly Recommended !!

    vkhastro1(Ontario, Canada), from an online thread entitled, Skywatcher 130f/5PDS-mini review

    Congrats on your new scope! 

    My experience mirrors yours. It is kind of an “unknown” scope, but for my own application it is working better than the Comet Catcher in spite of being smaller and “slower.”

    This scope is kind on the stealth list because when I say I have a 130mm f/5, everyone thinks it is a typical 130mm with small illuminated field and 1.25″ focuser and most do not seem to be aware of the 130 PDS.

    vkhastro1, on 30 Aug 2019 – 5:19 PM, said:

     

    95% enhanced 1°/2° mirrors – brighter view than my larger 140mm f/3.64 Comet Catcher

    optical testing – easily 1/8 wave or better

     

    These are factors that I used in my decision to move from the Comet Catcher to the 130 PDS.  Now my situation was that I am using image intensified eyepieces and I came to feel that the Comet Catcher was punching well below the f/3.6 spec.

    Some of this I thought was maybe due to the need to re-coat the mirrors, but after a painful testing sequence, I determined that the mirrors were OK, but that they were just not transmitting a lot at longer wavelengths (which is important for NV use) and this combined with the losses of the secondary shading and the corrector (which is where perhaps 10% of the loss in near infra red is coming from) meant that the scope simply was not as bright as I thought is should be. I actually think that the entire system transmission (including secondary shading) of the Comet Catcher really does cause it to loose a lot of brightness. I came to feel that the CC was simply much dimmer than it should be for a 140mm f/3.6 scope.

    The other issue I had with the Comet Catcher was the sled focuser and the awkward nature of trying to get it to work with a filter wheel.  The 130 PDS though, with its 2″ focuser with plenty of travel made it easy to use a filter wheel.

    One important point though is that while it is an “Imaging” scope, I don’t think it will fully illuminate an APS-C size sensor.  My NV monocular has an 18mm image circle, and I can see that there is a little illumination falloff at the edge.  Not bad, but it does not appear to have a fully illuminated circle bigger than maybe 12mm. Probably good for an APS-C with some cropping maybe or a 4/3.

    Anyway, as much as I loved the light weight and simplicity of the Comet Catcher, I came to feel that it was much dimmer than the numbers suggested and moved to the 130 PDS and like you, I really feel that it is brighter than the Comet Catcher was. 

    Nice scope.   Not many around as far as I can tell though.  

    130PDS R.jpg

    (Also, the image scale was a plus.  An added bonus was that I had enough focuser travel to use the Barlow lens mounted in one of my filter wheel positions.  This Barlow gives me the ability to bump up the power by about 1.5x just by turning the filter wheel and refocusing.  That is a nice benefit.)

    Good review of what appears to be a relatively unknowns scope.  Hope you are enjoying it!

    Eddgie, from an online thread entitled, Skywatcher 130f/5PDS-mini review

    Very informative comments. I picked up one of these a few weeks ago and use it on a Skywatcher Star Discovery Go To mount that I already had. Quick to set up and cool down, great optics and works really well with my Vixen LVW eyepieces. Nothing to dislike at all.

    brisdob(Brisbane, Australia), from an online thread entitled, Skywatcher 130f/5PDS-mini review

    We are looking into this model and it’s larger models currently.

    Skyward Eyes( Skywatcher USA Vendor), from an online thread entitled, Skywatcher 130f/5PDS-mini review

    For a number of years I had a SpaceProbe 130 ST fitted with a 2 inch Focuser. I normally used it with a Paracorr.. A Paracorr would address the need for an extension tube.

    I have said this before.. a good 130 mm F/5 Newtonian is the closest thing an affordable 4 inch apo Refractor that exists… The 130ST was quite good on planets and doubles as long as it had an hour or so to cool.

    I remember one dark night.. I swapped out my TeleVue NP-101 for the 130 mm F/5  with the Paracorr and 31 mm Nagler..it was scary how good it was.. 

    4920795-SpaceProbe 130ST Starpad.jpg

    Jon Isaac(San Diego, California, USA), from an online thread entitled, Skywatcher 130f/5PDS-mini review

    Ya don’t say; I got me one of them there ‘scopes….ken. I’ve no’ got the 2″ focuser mind, but I dinnae really need it. My bestest grab ‘n’ go ‘scope ever. Eye.

    Mr. Hardglass

    I’m a massive fan of 130 f5’s, even on the ota’s that are limited to 1.25″ ep’s. Very easy to mount scopes, and, when they have decent optics, great all around performers.

    Kerry R.( Mid-west Coast, Michigan, USA), from an online thread entitled, Skywatcher 130f/5PDS-mini review

    I have been using this telescope for around 6 months now on my evolution mount as an eaa platform. For the cost, it makes an excellent alternative to my 925 for wider field views and it can reach zenith with no problems.

    Barkingsteve, from an online thread entitled, Skywatcher 130f/5PDS-mini review

    ***

    FINALLY a Dob I really enjoy.

    Been through many different sizes, ranging up to 16 inches.  For me, a 12.5″ Dob is in the goldilocks zone.  Big enough to astound me with the views, but small enough to use every clear night.

    I can’t get enough.  In just 11 weeks of ownership, I’ve used it 42 times, including several trips to dark skies (3.5 hours each way).

    Ryan built a masterpiece.  It’s wonderfully engineered & built.  The telescope is so easy to assemble & disassemble. 

    In use, it is sheer joy.  The movements are silky smooth, requiring little pressure to track an object even at 300x.

    And the views?  Just mind-blowing.  Never thought a reflector could be so sharp and have such stark contrast.  This is the first time I’ve looked through a Zambuto mirror, and the views are as close to a refractor as I’ve ever seen in a mirrored telescope.

    During the last new moon, at extremely dark skies, I pulled the old M13/NGC6207 trick on an observer.  I got her to focus on NGC6207 at 250x.  After several minutes, I asked her to nudge the scope downwards slowly.  A gasp soon followed.  Then the hooting & hollering.  I understood her enthusiasm.  M13 looked photographic.

    Ryan was very gracious throughout the build process.  He promptly & politely answered all my emails, and was very patient, despite my impatience.  He is a master of his craft, and actually converted me from a refractor guy, to someone who can enjoy the night-sky using both types of telescopes.

    Attached Thumbnails

    • CN (2).JPG

    Magnitude 7, from a thread entitled, New Moon Telescope 12.5″ Zambuto refract… er… reflector.

     

    Aperture. Obviously of a decent quality, but aperture is what reveals detail.

    Small telescopes deliver a low magnification sharp looking view, but the fine detail doesnt exist. Its sharp because the magnification is low.

    Double the aperture, double the resolution, simple as that, provided the atmosphere obliges! Which it does more often than some people would maintain.

    Happy Limpet(Southampton, UK), from an online thread entitled, What’s more important.

    If you’re going to use a reflector, mirror quality is very important. I learned this when I had my 2001ish vintage Nova mirror refigured by Mike Lockwood this year. One of the biggest differences I noted was the moon. Before, I could see features on the moon, but the smaller ones could not really be seen, or made sense of, when examined closely. It’s a hard thing to describe, but it was something I noted often, and found frustrating. Detail in the refigured mirror is much clearer in this respect, probably more refractor-like.

    If refractors give a more tightly-controlled image than a similar-quality reflector, then that would be the way to go for lunar.

    I wonder how much the resolution advantage of a large aperture reflector is lost due to diffraction, coma, viewing through a wider expanse of air and a filter, compared to a more modestly sized apo. Maybe you really need to compare apos to apos.

    Mike Tahitub, from an online thread entitled, What’s more important.

    posted 09 October 2019 – 08:16 AM

    MikeTahtib, on 09 Oct 2019 – 10:26 AM, said:

    I wonder how much the resolution advantage of a large aperture reflector is lost due to diffraction, coma, viewing through a wider expanse of air and a filter, compared to a more modestly sized apo.  Maybe you really need to compare apos to apos .

    Diffraction – essentially none.

    Coma – none if using a coma corrector, very little otherwise (depending on f ratio)

    Viewing through a wide expanse of air – none, assuming you know how to get to thermal equilibrium (clue – use fans, its easy)

    A filter? none also

    How much extra money stays in your pocket? Vast.

    Reflectors rule.

    Happy Limpet(Southampton, UK), from an online thread entitled, What’s more important.

    Jon, my experience has been thus – with my Celestron Omni 102mm f/10 (now retired), the moon looked very good, detail was good, contrast as good as could be expected for an achromatic scope, CA was well controlled, but still present. With my SW 120 ED, more detail stood out, I was beginning to see an almost 3D view of things, especially along the terminator. I could also bring the magnification up a bit more than the 102mm, but the seeing conditions had more impact. And CA? What CA?

    With my 10 inch reflector, it is an OMG experience… I had it out Monday night and it quickly reminded me why I love this scope. The detail and contrast that is visible is like being in a Lunar lander on approach… words simply can’t describe the view. The 3D appearance was eye popping. It was a decent night, not great, with the seeing like a 3/5, so at higher mags, there was a bit of waviness at times, but mostly good. Keep in mind that my 10 inch reflector is an ATM scope, so a lot of attention was put into getting top performance.

    This has just served to remind me that a good refractor is no slouch… but has some limitations. A good reflector with some aperture is magical.

    Good hunting!

    Seabee 1, from an online thread entitled, What’s more important.

    My favorite scope for lunar visual is my 8″ f/9. When seeing is good the view is tack sharp. The best view ever was with my 25″ on a extremely steady night. I was hitting 1000x and still had a sharp image.

    Like Jon, no filter.

    Keith Rivich(Cypress, Texas), from an online thread entitled, What’s more important.

     

    More on Double Stars with a  commercial 8″ f/6 Newtonian

    This report is the fifth installment of a series of observational investigations I have made using an 8 inch f/5.9 reflecting telescope.

     

    Check out this link for goals and methods used in this study:

    https://www.cloudyni…-and-monoceros/

    Corona Borealis
    COU 610 Theta (15329+3122) mags 4.27/6.29; pa = 199°; sep = 0.85“, (orbital estimate for 2019.3 is a better fit with historical 4th Int. Cat. data vs last precise from 2016)
    345x, 460x:  single star
    627x:  brightening of diffraction ring that resolves to small dot that is just split 20% of time; at resolution limit and very challenging; re-measure of separation desired

    Draco
    HU 149 (15246+5413) mags 7.48/7.62; pa = 270°; sep = 0.665“, (2016, last precise; solid data)
    345x:  moves past elongated to notched (snowman) 30% of time
    460x:  at resolved/split border as seeing allows; both stars are light yellow-orange
    627x:  resolution aided with orange filter under excellent seeing conditions; a bit above resolution limit

    Image below is from 2017.444

    STF 2054AB (16238+6142) mags 6.15/7.09; pa = 351°; sep = 0.943“, (2017, last precise; solid data)
    345x:  easily seen as split 100% of time to two white stars of slightly dissimilar magnitude; above resolution limit
    image below is from 2019.455

     

    STF 2218 (17403+6341) mags 7.08/8.37; pa = 308°; sep = 1.476“, (2015.5, Gaia DR2; solid data)
    345x:  split 100% of time to two whitish stars; averted vision aids visualization of the fainter secondary; above limit

    STF 2403 (18443+6103) mags 6.25/8.35; pa = 278°; sep = 1.061“,  (last precise, 2011; solid data)
    345x:  seen as just split 50% of the time; both stars are yellow with the much smaller secondary sitting a bit past the first diffraction ring; above resolution limit
    There may be a number of observations for this one as it is part of the Sissy Haas Uneven Double Project

    STT 369 (19071+7204) mags 7.82/7.91; pa = 8°; sep = 0.684“, (2015.5, Gaia DR2; solid data)
    345x:  just split when seeing allows; both stars are yellowish-orange with secondary a bit smaller
    460x:  easier to see as split; above resolution limit

    MLR 12 (18293+8235) mags 8.90/9.12; pa = 222°; sep = 0.689“, (2008, last precise; data is old)
    345x/averted vision:  mostly pointy
    460x/averted vision:  much smaller secondary seen as resolved only 20% of the time—very difficult; right at resolution limit; separation re-measure needed

    STT 312AB Eta (16240+6131) mags 2.80/8.20; pa = 143°; sep = 4.676“,  (2015.5, Gaia DR2; solid data)
    345x:  secondary is a tiny speck of light well separated from the primary; held steadily in view on nights of better seeing; above resolution limit

    Hercules
    COU 107 (16169+1948) mags 9.02/9.61; pa = 113°; sep = 0.609“, (2009, speckle; data is old, scant)
    345x:  very faint; merely a bit elongated; below resolution limit; important data point to assess faintness factor; re-measure of separation needed

    STF 2107AB (16518+2840) mags 6.90/8.50; pa = 107°; sep = 1.443“,  (2015.5, Gaia DR2; solid data)
    345x:  easily split; both stars are whitish and the secondary is quite a bit smaller than the primary (but not tiny); above resolution limit

    A 350 (16540+2906) mags 9.47/9.61; pa = 144°; sep = 0.630“, (2019.542, own measure; considered solid because in line with 4th Int. Cat. trend)
    345x:  possibly pointy (not resolved); faint!
    460x/averted vision:  barely resolved when seeing permits with the secondary appearing just a bit smaller versus the primary; at resolution limit; important data point to set faintness factor

    Image below is from 2019.542

    BU 627A, BC (16492+4559) mags 4.84/8.45; pa = 40°; sep = 2.116“, (orbital estimate for 2019.4; system is opening; value is in line with last precise [2.06”] and Gaia DR2 [2.105”])
    345x:  easily split; both stars are white and secondary is quite small; above resolution limit
    Inverted image shown below is from 2017.501

    BU 812 (16071+1654) mags 9.06/9.36; pa = 96°; sep = 0.73“, (2011, last precise; data may be incongruent with historical 4th Int. Cat. values)
    345x/averted vision:  image moves past elongated to notched about 40% of time showing two similar magnitude, faint stars; a re-measure of both separation and delta mag is desired; considered a bit above resolution limit

    A 228 (17063+2631) mags 9.31/9.88; pa = 13°; sep = 0.658“, (2019.553, own measure; system is opening)
    345x/averted vision:  image is at the elongated/resolved border; discs are tiny—very faint!
    460x/averted vision:  resolved about 50% of the time; a bit above the resolution limit
    Note:  listed magnitudes are from Hipparcos, not Tycho
    Image below is from 2019.533

    HDS 2446 (17177+3717) mags 4.62/8.53; pa = 143°; sep = 0.918“, (2010, last precise; solid data)
    460x:  split ~100% of time on night of very good seeing; adding an orange filter to the optical train causes the secondary to nearly disappear which explains the exceptional difficulty experienced imaging this object; above resolution limit

    STF 2315AB (18250+2724) mags 6.57/7.77; pa = 115°; sep = 0.600“, (orbital estimate for 2019.4; solid data)
    345x:  merely a bit oblong
    460x:  moves past elongated to a snowman shape about 30% of the time—stars clearly of dissimilar magnitude; on border of resolved but never actually seen as resolved; appears to be just below resolution limit
    Inverted image shown below is from 2017.512

    BU 641 (18218+2130) mags 7.03/8.66; pa = 341°; sep = 0.78“, (2015, last precise; solid data)
    345x:  moves past pointy to resolved about 10% of the time; secondary is much smaller
    460x:  seen as split when seeing allows image to sharpen (~30% of time); above resolution limit

    STF 2339AB, CD (18338+1744) mags 7.45/8.67; pa = 277°; sep = 1.482“, (2018, last precise; likely solid data)
    345x:  easily split to show fine magnitude contrast pair with primary seen as white and secondary as light orange; above resolution limit
    460x/averted vision:  secondary [CD] now appears elongated—it has a rho value of 0.492” and is known as WAK 21CD—a very nice bonus!

    A 238 (18114+2519) mags 8.59/9.55; pa = 74°; sep = 0.632“, (2019.548, own measure)
    345x:  persistently pointy
    460x/averted vision:  moves past elongated to resolved 20% of time; secondary is tiny; at resolution limit
    Image shown below is from 2019.548

    A 2093 (18054+1624) mags 9.09/9.85; pa = 226°; sep = 0.642“,  (2008, last precise; data is old but considered solid)
    460x:  very faint, elongated rod that presents as resolved perhaps 5% of the time; at or slightly below resolution limit

    TDT 1042 (18461+1328) mags 8.85/9.65; pa = 274°; sep = 0.7“,  (2009, last precise; data is old, not solid)
    345x:  merely point; stars are faint
    460x:  sharpens to resolved from a rod shape about 10% of time; at resolution limit; re-measure of separation needed

    STF 2084 Zeta (16413+3136) mags 2.95/5.40; pa = 112°; sep = 1.373“,  (grade 1 orbital estimate for 2019.211)
    345x:  light orange secondary just touching bright white primary—beautiful!  Above resolution limit
    Image shown below is from 2019.452

    STF 2203 (17412+4139) mags 7.72/7.81; pa = 293°; sep = 0.757“, (2015.5, Gaia DR2; solid data)
    345x:  just split to two white stars—not difficult; above resolution limit

    Libra
    STF 3090AB (15087-0059) mags 9.09/9.34; pa = 287°; sep = 0.627“, (2017, last precise; little corroboration from 4th Int Cat.)
    460x:  elongated only; never resolved
    627x/averted vision:  never moved past elongated; below resolution limit; not sure why this object is so difficult—a re-measure of separation is desired

    I1269AB (15249-2322) mags 8.73/8.84; pa = 199°; sep = 0.654“, (2015.5, Gaia DR2; solid data)
    345x/averted vision (best conditions):  resolved to two white stars of very similar magnitude about 30% of the time; at or slightly above resolution limit; important data point to establish minimum rho value for calculator

    BU 225BC (14255-1958) mags 7.16/8.37; pa = 91°; sep = 1.285“, (2015.5, Gaia DR2; solid data)
    345x:  split 100% of time showing the primary as white and the secondary as light yellow and smaller; above resolution limit; a beautiful triple with the AB pair designated SHJ 179 or H N 80

    HJ 4756 (15197-2416) mags 7.90/8.27; pa = 242°; sep = 0.574“, (2015.5, Gaia DR2; solid data)
    345x/averted vision:  moves past elongated to notched 50% of time (never resolved)
    460x:  resolved 50% of time; discs are very small and appear similar in magnitude; a bit above resolution limit; important data point to establish minimum rho value for calculator

    A 81 (15089-0635) mags 9.43/9.76; pa = 41°; sep = 0.68“, (2005, last precise; data is old and scant)
    345x/averted vision:  rod only; stars are very faint
    460x/averted vision:  moves past elongated to resolved at most 5% of the time; below resolution limit; re-measure of separation desired

    Lyra
    HU 1300 (19202+3411) mags 8.92/9.56; pa = 184°; sep = 0.74“, (2015, last precise; data is solid)
    345x/averted vision:  mostly a single star, but possibly rod-shaped; faint!
    460x:  at most rod-shaped (never resolved); below resolution limit which makes this object an outlier—further investigation warranted

    A 703 (19072+4451) mags 9.01/9.28; pa = 189°; sep = 0.57“, (2010, last precise; likely solid data)
    as yet unobserved; important data point to establish faintness factor for resolution calculator

    BU 648AB (18570+3254) mags 5.34/7.96; pa = 243°; sep = 1.303“, (grade 2 orbital estimate for 2019.3)
    460x:  small brightening apart from the primary that sharpens to a small disc that is seen as split 50% of the time
    627x:  split 100% of time; secondary is much smaller, both stars appear white; above resolution limit

    Have you observed or imaged any of these double stars?  I would love to hear of your endeavors with these objects.  Are there other, similarly challenging objects in these constellations that I have missed?  Let me know.

    Nucleophile(Austin, Texas, USA), from an online thread entitled; 8 Inch Reflector Investigations. Part V: Corona Borealis, Draco, Hercules, Libra, and Lyra.

    Hu149_DRA.jpg

    STF 2054AB

     

    STF2054AB_DRA.jpg

    A350_HER.jpg

    STF2315AB_HER.jpg

    STF 2084 Zeta

     

    STF2084_Zeta_HER.jpg

    STF 2084 Zeta

     

    STF2084_Zeta_HER.jpg

    A238_HER.jpg

    Nucleophile(Austin, Texas, USA), from an online thread entitled; 8 Inch Reflector Investigations. Part V: Corona Borealis, Draco, Hercules, Libra, and Lyra.

    Excellent as always Mark!

    Here are some of my observations from your list, plus a few others you might try:

    Cou 610 AB: 8″ 667x: Notched/snowman at best moments.  B definitely fainter and almost blue.  Very faintly split, looks like a blue appendage.  20″ diffraction is too messy.

    STF 2107 AB: !! 12.5” This was a CDSA plot find, didn’t expect it to be special.  Yellow and orange pair, very close ~1.5″, 1 delta mag.  Very pretty.

    STF 2315 AB: 12.5” 553x.  Near contact / overlapping disks, 0.5 delta mag.

    BU 641 AB: 12.5” 553x. !! Extraordinary!  Moderately bright A and much fainter B, <1″ separation.  Seeing needs to still.

    STF 2339 AB-CD: 20”: 533x: White and dull white B. Close but well separated, ~1″ [AB-CD seen. AB is Hu 322 1 delta mag 0.2″, not noticed]

    STF 3090 AB: 12.5” Notched to hairline split at the best moments. Faint pair, tough. Seeing not good enough to go above 553x. [AB seen; AC fainter and wider.]

    BU 648: 8″ 333x: 3 delta mag, at first diffraction, needed critical focus and seeing.

    OTHERS:

    Met 9: 8″ 205x nothing.  8″ 410x suspect elongation.  667x see a fleeting, bluish point just outside of first diffraction ring.  A is light yellow orange and bright; 2 delta mag. to B.  A feels elongated / egg shaped.  At 20″ and 667x the seeing is too messy though there is a knot in the diffraction where I had noticed the point with 8″.  Strong feeling A is elongated.
    12h 54m 39.98s +22° 06′ 28.8″ P.A. 51 sep 1.7 mag 5.70,7.77 Sp F8V+M2-3V dist. 33.85 pc (110.42 l.y.)

    STF 1967 = Gamma CrB: Definite mis-shape, oval to egg.  8″ 667x.
    15h 42m 44.57s +26° 17′ 44.3″ P.A. 104.6 sep 0.22 mag 4.04,5.60 Sp B9V+A3V dist. 44.78 pc (146.07 l.y.)

    STF 2289: Just split in 20″ at 205x, but flaring. 333x had messy diffraction. 8″ mask at 333x gave clean disks, split, ~0.7″. Dull yellow and yellow-red colors.

    18h 10m 08.69s +16° 28′ 35.0″ P.A. 215.3 sep 1.24 mag 6.65,7.21 Sp A0V+G0III dist. 263.85 pc (860.68 l.y.)

    STT 359: !! Kissing 8″ 333x, hairline split 667x. 20″ too diffracted. Near equal white A and bluish white B.
    18h 35m 30.40s +23° 36′ 19.9″ P.A. 3.7 sep 0.75 mag 6.35,6.62 Sp G9III-IV dist. 144.3 pc (470.71 l.y.)

    A 260 AB: 20″ 667x: At 8″, small and faint suspected split at 333x: 8″ 667x stars are hazy. At 20″ 667x got a clean wide split two hard paints of stars.
    18h 57m 34.07s +32° 09′ 20.2″ P.A. 244 sep 0.8 mag 9.17,9.60 Sp A0

    STF 2422: 8″ 333x: Excellent hairline split at 333x with 8” mask. Near equal white stars. Picked them out in a crowded field, suspected elongation right away, split with seeing as I centered it in eyepiece, and from then it was a steady split
    18h 57m 07.83s +26° 05′ 45.1″ P.A. 68 sep 0.8 mag 7.93,8.25 Sp A2IV dist. 156.25 pc (509.69 l.y.)

    AGC 9 AB = Sulafat: 8” 533x: B star immediately picked out of A’s glow like a piece of debris suspended in the explosion, or a planet hanging in the halo.
    18h 58m 56.62s +32° 41′ 22.4″ P.A. 307 sep 13.5 mag 3.24,12.10 Sp B9III dist. 190.11 pc (620.14 l.y.)

    HO 92 AB 20″ 667x: ! Beautifully well split, had an instant of perfect images. White pair near equal.
    19h 00m 59.89s +32° 33′ 11.6″ P.A. 40 sep 1.3 mag 10.59,10.85

    COU 1156 AB 20″ 667x: ! Near qual small and at best moments a clean split, still, just nice points. great star.
    19h 00m 34.25s +33° 01′ 24.8″ P.A. 111 sep 0.7 mag 11.14,11.25

    STF 2461 AB = 17 Lyr: 20″ 667x: ! Huge delta mag. B is obvious in 20″, though A’s diffraction was horrible. Used 8” mask to clean it up but the B star momentarily disappeared, though I could eventually pull it back out with seeing and critical focus. 4 delta mag.
    19h 07m 25.58s +32° 30′ 06.2″ P.A. 281 sep 3.2 mag 5.26,9.10 Sp F0V dist. 41.58 pc (135.63 l.y.)

    mccarthymark(San Francisco, California, USA), from an online thread entitled; 8 Inch Reflector Investigations. Part V: Corona Borealis, Draco, Hercules, Libra, and Lyra.

    I like using my 105mm APO on double stars over my larger scopes just because it gives nicer images even when the seeing is below average.  I still get nice round stars but the whole image kind of bounces almost like my clock drive is making it bump up and down a little.

    An 8″ scope will be affected 4 times as much as a 4″ on the same night, so in this case aperture doesn’t rule in below average seeing.

    If I am going specifically after doubles, I tend towards my 10 inch Dob rather than any of my refractors.  One reason is for it to perform it’s rock solid best, I need to set out up before sunset and run the fans for considerably more than an hour.

    If the seeing is on the good side and I started with a 4 or 5 inch, I’m stuck.  

    For closer doubles, maybe 1.4″ or closer, the 10 inch provides wider splits under most circumstances because it’s Airy disk is so much smaller. A 1.14″ double is a Dawes limit split in a 4 inch, in the 10 inch it’s a wide split and I’m not fighting both the large Airy disk and the seeing.

    I’m not sure about your factor of 4 in terms of the effect on the image. I am not looking so much for a pretty image, I’m looking for closer splits. Antares is usually a challenging split in a 4 or 5 inch but last year I made the split in my 22 inch with Antares quite low on the horizon, no way in a small scope.

    It wasn’t pretty but it was very wide, bright and apparent. It made me realize just how small the airy disks are in a scope that size.

    With any scope but a larger scope in particular, the outer seeing aberrated region can as an extended object while it surrounds the region where the airy disk is brighter. Cranking up the magnification can increase the contrast by dimming that outer region.

    Jon Isaac( San Diego, California, USA), from an online thread entitled Effects of Bad Seeing: Double Stars

    This was my second dark site session with my new telescope.

    A week before, I had to cut the session short as humidity became unbearable – spider and shroud started dripping.
    I want to share my impressions of this device now that I had a full session.

     

    Logistics first.
    This is not a small scope so I got a folding aluminum ramps for loading it. This way, I can load the scope alone and it is faster than loading my SW 12″ collapsible.
    just need to make sure that mirror box is tilted a bit so the bearing will not hit the car ceiling.

    FHh9hdim.jpg

    Truss and shroud are light and have plenty of room.
    For a 20″ monster, the process of loading is easy enough.
    If not totally lazy or must, the scope can be loaded/unloaded without ramps.

    The road to the dark site is about 2.5 hours drive. I have been making this trip every month for over a year now and love the drive.
    re4jgQFl.jpg jELqQBTl.jpg

    I was the first on site, about an hour before dark.
    Unloading was simple enough and once everything was out of the car, I went to assemble the scope

    Assembly is quick, Truss to mirror box, fasten the bolts, UTA on Truss, fasten the bolts and then the shroud.
    This takes few minutes and is easy, just as Ryan show in his Youtube channel.

    lIjKInHl.jpg 60bzIWYl.jpg

    For collimation I use the Farpoint 2″ collimation kit – laser and cheshire.
    Even after 2.5 hour drive, last part of it is off-road, collimation did not drifted by much.

    The entire process of assembly + collimation takes about ~20 minutes.
    With camp set – tent, table chairs, I still had time to dress for the cold before total darkness.

    I was lucky to see the gathering of Venus, Moon and Jupiter with Saturn watching from above.

    That was an amazing sight!
    wrqf0Bjl.jpg

     

    Observations:

    First I revisit the Vail nebula.
    Eyepiece – Nagler 31mm filtered with O-III
    Started with the Western part of the nebula from the tip through Cy52 to its bottom part. The amount of details was insane.
    The Eestern part as equally stunning.

    The central part of the nebula was nicely visible.

    Tonight’s plan was to go through objects in Cassiopeia, Perseus, Andromeda, Orion and Ursa Major.

    Double cluster fits nicely into the FOV of the Nagler 31mm. Very sharp image.
    Raising magnification a bit, still could see both clusters within view.
    Next came the Owl cluster, M103, NGC 663 and more.
    Pacman nebula was also nicely visible, I will have to revisit this object to figure out more details.

    I did a quick detour to view M15. This cluster is magnificent! raised magnification to 135 and the cluster could be resolved nicely.
    With magnification of over x200 which is reserved for such objects, I could easily distinguish stars almost to the core.

    Andromeda Galaxy showed two dust lanes, one very distinct and the other is fainter. I never saw so many details in the arms before.
    Both companions – M110 and M32 also fit the FOV.

    Pinwheel Galaxy, another showpiece object also provided much details.

    In Orion, I saw the bubble nebula for the first time.
    M42 is majestic as ever, all the details are just fantastic, the nebula is closing full circle, wings full of details. With filters, different details emerge.

    The 20″ collects so much light that even a cellphone camera could yield details (I had to try…)
    Eh3jJUPl.jpg

    Horsehead nebula was not visible when it was 30-40 degrees but when reaching over 50 degrees altitude, provided a lots of details.
    The nebulusity from Alnitak towards HD 37806 was visible with the horse interrupting it like a finger obscuring the view.

    Last area covered was Ursa Major – galaxy hunting.
    Finding galaxies with this huge field of view is fun and easy.

    This session yielded many objects, over 50 were documented, many were not viewed enough and will be revisited to get more details.

    My impressions so far:

    I am very happy with my new telescope.
    The difference in view from my 12″ is everything I expected and more, some objects are actually visible and others show so much more details.

    Views are wide, crisp and sharp, especially when conditions allows.
    Transportability and the ability to handle it by myself is exactly why I opted for NMT in the first place.
    Mechanically this is a wonderfully constructed device. Movement is smooth in both axis but firm enough not to shift when switching eyepieces.
    Balance is the same without eyepiece or with Paracorr-2 + Nagler 31mm. I guess Binoviewer will require some counterweight – Ryan provided rails for counterweight, just in case.
    Collimation lasts in full movement range and during the session – I did not check, but felt no view degradation – will test it on the next session.

    Scope Basking in the morning sun after a long night
    AL5Ge1Al.jpg

    ilan Shapira( Israel), from an online thread entitled; My NMT 20″ f/3.3

    Got back out for an hour or so and tried out my higher powered plossls. Seeing was not great and I’m under white zone skies with limited sky to point at from my driveway but I make it work. I can tell the scope is a bump up from my ST80 with the higher powered eyepieces. To my newb eyes collimation appears good. Stars weren’t exactly pinpricks at high power but they’re round and turn into nice round donuts in and out of focus.

    Took a look at a dimming beetleguese, Uranus with I think a hint at its moons. The Pleiades looked great back down with the 32 plossl.

    M42 looked better than I’d ever seen it at all powers. And it looks spectacular to my eyes with my $13 UHC filter.

    It’s definitely a different experience looking through the eyepiece on this reflector as opposed to my mak and my refractor. Just a bit higher at most views than is perfect viewing on my camp stool, but being able to rotate the tube in the rings brings it to an accessable height.

    (If this post would have been more appropriate in the beginner forum I apologize.)

    Tannhauser Gate, from an online thread entitled, First Light with a cheap 130/650/f/5

    I like 130 mm F/5 Newtonians. If the optics are decent, they’re the closest thing to a budget 4 inch apo you can buy.

    The focuser appears to be a Crayford, that’s a good thing. It looks like a 2 inch Orion focuser,, there’s no adapter?

    Have fun..

    Jon Isaac( San Diego, California, USA), from an online thread entitled, First Light with a cheap 130/650/f/5

    Actually it goes a little deeper than any 4 inch Apo and resolves significantly closer double stars(down to 0.9″) in the hands of experienced observers and good seeing conditiions.

    Mr Hardglass

    That’s a sharp looking scope.,I love my 130.,it’s my most used scope because it puts up great views and is easy to carry out and be viewing.,cheers.

    Clearwaterdave,(Western Maine, USA), from an online thread entitled, First Light with a cheap 130/650/f/5.

     

    Attached Thumbnails

    • 20190327_183143.jpg

     

    Because seeing was good at Christmas I observed Sirius. In 2012 I had great difficulty to see the Pup, but now it was rather easy. I tried to make my pencil sketch as realistic as possible. I added some color in GIMP but I’m not 100% satisfied with the result.

    Which version do you prefer?

    Attached Thumbnails

    • Sirius B afgewerkt grijs 600.png

     

    Attached Thumbnails

    • Sirius B afgewerkt kleur 600.png
    Jef De Wit(Hove, Belgium), from an online thread entitled Sirius B (the Pup)

    To be continued…………………..

     

    Neil English unearths plenty more historical evidence testifying to the prowess of Newtonian reflectors in his large historical work, Chronicling the Golden Age of Astronomy, newly published by Springer-Nature.

     

    De Fideli.

     

    For the Record.

    Plotina: raising the bar for grab ‘n’ go astronomy.

     

    2018 was not an unusual year here in Scotland, as astronomical observing and associated note-making are concerned.

    Total number of nights where observations were made in 2018: 137

    Percentage of nights available for observation in 2018: 37.5 per cent.

     

     

    2019: I recorded 135 nights of clear or partially clear skies. This represents 36.9 per cent of nights available for observation.

    These numbers continue to be in accord with the claims of several British historical observers; T. W. Webb, William F. Denning & Charles Grover.

    For more details on this interesting topic, see my 2018 book: Chronicling the Golden Age of Astronomy.

     

    De Fideli

    Product Review: The Celestron Trailseeker 8 x 32.

    The Celestron Trailseeker 8 x 32 mid-size binocular.

    Are you looking for a good quality mid-size binocular but don’t have £1000+ to spend on a Swarovski or a Leica or some such? Perhaps you’re looking for a nice Christmas gift for a loved one or a friend? Well, the Celestron Trailseeker 8 x 32 binocular could well be all the instrument you need!

    If you’ve been following my binocular blogs, you’ll know that I have had to follow a very steep learning curve in order to bring my readers genuinely good bargains. And while it is generally true that you get what you pay for, there are always products that surprise in very pleasant ways, and this little binocular is one such instrument!

    Celestron is not a name you’d normally associate with a high-quality roof prism binocular, but their optical engineers have successfully designed a great product in their Trailseeker range. The Trailseekers all feature full broadband multicoatings on all optical surfaces. The BAK-4 Schmidt-Pechan prisms are both phase and dielectricly coated to increase light transmission to the order of 90+ per cent, making it as efficient as ultra-premium models costing many times more.

    The binocular measures 4.8 inches wide and 4.8 inches deep, standing just 1.9″ high; so very compact and easy to store in a backpack or small carry case. The binocular can be easily mounted to a tripod or monocular for additional stability.

    My flashlight tests carried out indoors, as well as those conducted out of doors on bright street lighting and strongly backlit scenes showed that this model has excellent stray light and glare control. Indeed, its baffling of stray light is up there with the very best binoculars I have had the pleasure of testing. I was literally blown away by how resilent this binocular is to the intrusion of stray light! What that means in practice is that you get very high contrast images, rich in detail that would impress most anyone who tries them out!

    The Trailseeker has a very robust magnesium alloy chassis; a feature often only found on premium models.

    The binocular has a very strong and robust magnesium alloy chassis that is often only offered in the most expensive brands. It is also remarkably lightweight, tipping the scales at just 454g(16 oz). The strong, lightweight alloy frame also means that it will withstand knocks and bumps better than other models having cheaper plastic or ploycarbonate housings. The optics are 0-ringed sealed and purged with dry nitrogen gas to prevent internal fogging during cold-weather applications and corrosion of any metal parts used inside the instrument. The chassis is finished in a thick, rubberised green armouring that has excellent grip and which protects the main body from the elements. The underside of the binocular has neat thumb indents that make gripping the instrument very intuitive.

    The underside of the Trailseeker has neat thumb indents that make handling the instrument very easy and intuitive.

    The eyecups are of very high quality. They are made from solid metal with a soft, rubberised finish that makes them very comfortable to observe through. The eyecups twist up with two stops and hold their positions very well indeed, with absolutely no play. The eyerelief is 15.6mm which is adequate for most eyeglass wearers. Close focus is about 6 feet and the field of view is a very generous 7.8 angular degrees(136m@1000m).The dioptre setting is located under the right ocular lens and has just the right amount of friction to keep it rigidly in place from day to day, and from week to week.

    The focuser and ocular lenses of the 8 x 32 Celestron Trailseeker.

    Optically, the 8 x 32 Trailseeker packs a very powerful whallop. The instrument arrived well collimated out of the box, as evidenced by the perfectly correlated left and right eye images of a chimney located about 150 yards in the distance. The images are razor sharp with a large central sweetspot, softening as you move toward the edge, just like any other binocular. Chromatic aberration is a total non issue(I think this issue in many good quality binos available today has more heat than light). I see a lot of amateurs making bold claims about how ED glass elements make the image ‘brighter’ but in reality, the brightness of the image in the best quality binoculars has little to do with ED glass and much more to do with the quality of the coatings(particularly those of the dielectric variety) employed on the roof prism. For example, I was quite taken aback when I tested this unit out in low light conditions during dusk, when they completely outperformed a very high quality 8 x 25 pocket binocular lavished with premium ED Schott glass and dielctric coated roof prisms. There was no magic though; the very efficient light gathering capabilities of the Trailseeker’s larger 32mm objectives stole the show; it was much brighter, no ifs or buts about it!

    A Curious Aside: I wanted to get to the bottom of this somewhat ‘fishy’ claim regarding ED glass, you know; that it gives brighter images and all that, so I decided to investigate some products on line. I mean, I can see why a better focused image in an ED instrument would confer a very slight advantage over a standard achromatic unit with the same coatings, but certainly not to the extent some folk have claimed in the past. Well, I didn’t have to search long before I stumbled on a comapny, Hawke, who make a few models of 8 x 32s, and out of sheer dumb luck(not really), I was able to compare the specifications of their Endurance ED 8x 32 and their Fronier HDX 8 x 32. As you can see from the specs, the Endurance ED does indeed have ED glass, while the Fronteir HDX does not. However, it is the latter that sells for a higher retail price(£259 as opposed to £199)! The one significant difference between these models is that the Endurance ED does not have dielectric coatings on the prisms while the HDX model does. And as this chap confirms, the HDX delivers the brighter image!

    So there you have it!

    I will further investigate these claims in a later blog, God willing.

    No’ bad ken?

    NB: The author has no affiliation with any of the binoculars discussed in any of his blogs.

    A good design feature: the deeply recessed (9mm) objectives are well protected from rain, dust and peripheral glare.

    Although not my favourite size of binocular, the 8 x 32 format is great for birding and other nature studies. Its greater light grasp and generous field of view will enable the user to work under fading light more efficiently and for longer than any pocket glass. The central focuser is well made but was a little on the stiff side when I first acquired it. But with regular use, it has loosened up nicely to allow good, fast focusing on mobile targets like birds in flight, or scurrying squirrels racing up and down a tree trunk. Going from one end of the focus travel to the other involves turning the focus wheel through one and a half full revolutions.

    The Celestron Trailseeker 8 x 32 has very high quality twist up eyecups which make viewing through them very comfortable and immersive.

    The little Celestron Trailseeker 8 x 32 produces very nice images of the heavens. Looking at a rising full Moon in a frosty winter sky showed very sharp, contrasty images rich in detail, with virtually no stray light that was all too easily evident in a few lesser instruments I have tested. Moving to the edge of the field does reveal some lateral chromatic aberration and some image softening but it’s perfectly acceptable to my eye. What is more, some of these off-axis aberrations can be effectively focused out. Star fields are beautiful and sharp with a jet black sky background, and the Trailseeker has served up very impressive views of some showpiece deep sky targets such as the Pleiades, the Hyades, the Sword Handle of Orion, the Alpha Persei Association and the great spiral galaxy in Andromeda. Stars stay sharp and pinpointed across the majority of the field, with only the outer 20 per cent or so beginning to show some enlargement. That said, I found this imperfection to be very acceptable. Indeed, you would have to shell out many times the modest cost of this binocular (£126) to get anything better in this regard methinks!

    Unlike many other high quality binoculars, the accesories that come with the Trailseeker are also of exceptional quality. You get a very nicely made carry case that fits the instrument perfectly(shown above). You also receive a very nicely padded neckstrap with a Celestron orange logo.  That said, I discovered a slight hitch when I attached the supplied neck strap; when I tried to fold it around the binocular to insert it inside the carry case, it proved very difficult and caused the case to bulge outward a bit more than my liking. In the end, I elected to attach a lighter but lower quality strap to the binocular as an interim measure. The instrument also comes with a good quality binocular harness, though I’ve not tried it out for size yet. In addition, the binocular comes with fully attachable rubber ocular and objective lens covers, a microfibre lens cleaning cloth, and a neat user manual in five modern languages. The package is protected by Celestron’s limited lifetime warranty.

    The Celestron Trailseeker 8 x 32 package.

    All in all, the Celestron Trailseeker is a most impressive piece of kit and it’s obvious that the company cut no serious corners in bringing these high quality instruments to market. I think it represents exceptional value for money in a market saturated by a string of  similarly priced, but lower quality offerings. Kudos to Celestron for making these instruments available at such an incredible price(they originally retailed for over £250 when first launched but are now widely discounted)!

    Disclaimer: The instrument was purchased from Tring Astronomy Centre, the staff of which proved very professional and who insured a super fast delivery.

    Additional Information:

    Promotional Video on the Celestron Trailseeker Binocular Range.

    BBR overview of the external features of the 10 x 32 Trailseeker Binocular.

    Don’t just take my word for it: read what other purchasers have said about the Celestron Trailseekers.

    BBR Review of the 10 x 32 Celestron TrailSeeker Binocular.

    BBR Review of the Celestron Trailseeker 8 x 42 Binocular.

     

    Neil English is the author of seven books in amateur and professional astronomy, including a 665 page history of visual astronomy: Chronicling the Golden Age of Astronomy, favourably reviewed by several amateur and professional astronomers.

     

    De Fideli.

    Old vs New.

    How does a classic Zeiss binocular square up to a modern roof prism binocular?

    Unlike telescopes, which are mainly used by dedicated amateur astronomers, binoculars, for obvious reasons, are owned and used by a much broader cross section of the general population. When my students get to know me, they will inevitably have to endure my unbridled enthusiasm for optical devices of all kinds lol, and that includes binoculars. One of my mathematics students, Sandy, expressed an unusual interest in some of my instruments, and he further informed me that his parents, who run a small ferrying business at Balmaha, on the shores of nearby Loch Lomond, used several binoculars in their everyday work. My interest was further piqued when Sandy told me that his grandfather owned a big Zeiss binocular, which was inherited by his father and would eventually be passed on to him in the goodness of time. I asked Sandy whether he would be willing to bring the Zeiss binocular by so that I could have a look at it. After checking with his parents, Sandy agreed and kindly allowed me to use it for a week in order that I could assess it and give it a good clean. Naturally enough, I jumped at the opportunity!

    The instrument, a Carl Zeiss Jenoptem 10 x 50W porro prism binocular, came in a lovely leather case; a far cry form anything made in this era.

    The Zeiss Jenoptem 10x 50W complete with original leather carry case.

    The instrument had no lens caps and so had accumulated quite a bit of grime on both the ocular and objective lenses over the years. The Jenoptem, which was manufactured in East Germany(DDR), featured a Zeiss multi-coating, which helped me to date it to after 1978, when the company apparently began to apply their anti-reflection coatings to all the lenses and prisms in the optical train. So my guess is that it was probably acquired in the early 1980s. I believe Zeiss Jena offered a higher quality porro 10 x 50 in the Decarem line around the same period, but I have not had the pleasure of testing one of these units out.

    The Zeiss Jenoptem is multi-coated.

    The instrument has a very Spartan look and feel about it. Weighing in at about 1 kilogram, the Jenoptem is built like a proverbial tank, with a central focusing wheel and right eye dioptre.Turning the nicely machined metal focusing wheel first clockwise, and then anti-clockwise, all the way through its trave,l showed that it was still in excellent working condition, with zero backlash and bumping that one usually encounters with cheaper porro prism binoculars.

    As expected from Zeiss, the Jenoptem has a very well made focuser that moves with silky smoothness and with zero backlash.

    To begin the cleaning process, I unscrewed the objective housings from the front of the binocular in order to get at the inside surface of the objective lenses, which had a significant amount of grime as well as a small amount of fungal growth. Using a good quality lens brush, I carefully removed much of the dust before using a microfibre lens cleaning cloth soaked in a little Baader Optical Wonder fluid. In just a few minutes I was able to remove the remaining grime on both the outer and inner surfaces of the binocular objectives, as well as the surfaces of the prisms in the rear module of the instrument. The ocular lenses were also given a good cleaning.

    The objectives of the Zeiss Jenoptem can be accessed by uncrewing the front of the binocular from the prism and ocular housing.

    I was able to verify that the prisms were indeed coated in the same way as the objectives, although I also discovered that the steel clips holding the prisms in place had rusted significantly over time. I did not attempt to clean the clips, as I judged that doing so might throw the instrument out of collimation.

    Note the rusted steel clip holding one of the prisms in place, as well as the anti-reflection coating of the second prism(after cleaning).

    The objectives on the Jenoptem after cleaning. Note the anti-reflection coatings.

    Seen in broad daylight, I was able to verify that the lens coatings had not suffered much in the way of wearing, looking smooth and evenly applied, giving a bluish or purple cast, depending on the angle of view.

    The appearance of the objectives in broad daylight after cleaning.

     

    And the ocular lenses.

    Optical tests:

    After screwing the objective modules back into place, I was now ready to begin my optical tests of this older Zeiss binocular. I compared the views served up by this instrument with those garnered by my Barr & Stroud 10 x 50 Sierra roof prism binocular that I use almost exclusively for astronomical viewing. After setting the right eye dioptre on the Zeiss to suit my own eyes, I started with an iphone torch test to assess how the instruments fared in suppressing glare and internal reflections.

    The Zeiss 10x 50W Jenoptem(right) and my Barr & Stroud 10x 50 Sierra roof prism binocular(left).

    Because the Zeiss does not have the same close focus (~2m) performance as my Barr & Stroud, I had to place my iphone torch several metres away in my hallway in order to get the Zeiss to focus on its light. As usual, the torch was adjusted to its highest (read brightest) setting. Comparing the two in-focus images, I could see that the Zeiss fared considerably worse than the Barr & Stroud. Specifically, it picked up two fairly bright internal reflections, as well as quite a lot of contrast-robbing diffused light, which rendered the Zeiss image considerably less clean and contrasted in comparison to my control binocular. The difference was quite striking!

    After dark, I aimed the binoculars at a bright sodium street lamp and again compared the images served up in both instruments. As expected, the Zeiss showed much more in the way of internal reflections, with a lot of diffused light that produced a fog-like veil around the street lamp. The Sierra 10 x 50 in comparison served up a much more ‘punchy’ image with much better control of internal reflections and far less of the foggy, diffused light evidenced in the Zeiss.

    Next, I compared the Zeiss and the Barr & Stroud Sierra on a daylight test, examining a tree trunk in the swing park about 80 yards from my front door. Again, the difference between both instruments was striking! Although the image was very sharp in the Zeiss at the centre of the field, it was noticeably dimmer than the Sierra. That diffused light I picked up in the iphone torch test created a foggy veil that significantly reduced its contrast in comparison to the control binocular. I was also able to discern many more low contrast details in the Sierra owing to its ability to gather significantly more light than the older Zeiss. The colour cast presented by both binoculars was also noteworthy. The Zeiss threw up quite a strong yellowish colour cast  to the Sierra, which showed a much more neutral cast in comparison.

    Examining the periphery of the same field also showed that the Sierra was exhibiting a larger depth of focus than the Zeiss, which was quite unexpected, as I had been given to understand that porro prism binoculars in general show more depth of focus than their roof prism counterparts. In addition, the Zeiss showed more distortion at the edges of the field than the control binocular.

    The Zeiss Jenoptem has very tight eye relief, which I estimated to be just 10mm. The Barr & Stroud Sierra, in contrast, has much more generous eye relief in comparison- 17mm – making it significantly more suitable for eye glass wearers. Indeed, I found it difficult to image the entire field in the Zeiss, having to move my eyeball around to see the field stops.

    In summary, these daylight tests clearly showed that the venerable Zeiss was no match optically for the Barr & Stroud 10 x 50 roof prism I had tested it against. The latter was simply in a different league to the former, no question about it!

    Handling in the Field:

    The Zeiss is rather big and clunky in my small hands and is more difficult to find that optimal position while viewing for extended periods. Weighing more than 200g more than the Sierra, it is also harder to hold steady. The significantly smaller frame of the Sierra roof prism binocular is much easier to negotiate, and is simply more comfortable to use. In addition, the Zeiss has no provision to mount it on a lightweight tripod or monopod, but the Sierra, like most other modern binoculars, does.

    Astronomical tests:

    Though the weather proved quite unsettled during the week that I tested the Zeiss, I did get a few opportunities to test it out on the night sky. Once again, I used my Barr & Stroud Sierra 10x 50 roof prism as a suitable control. My first target was a bright, waxing gibbous Moon fairly low in the southern sky. The Zeiss threw up more in the way of internal reflections than the Sierra. The colour cast of the lunar surface appeared more yellow in  the Zeiss compared with the cleaner images of the Sierra. As I expected from my iphone torch tests, the sky immediately arround the Moon was also brighter in the Zeiss, with noticeably lower contrast than the Sierra. Moving the Moon to the edge of the field also showed that the Zeiss threw up more distortions than the Sierra control binocular.

    Turning to Vega high in the northwest after sunset produced good on-axis images in both binoculars, but when moved to the edge of the field, the Zeiss threw up that little bit more distortion than the Barr & Stroud Sierra. The same was true when I examined the Pleaides and the Hyades in Taurus.

    Conclusions and Implications:

    The Zeiss Jenoptem was a good binocular in its day but is clearly inferior in almost every sense to the Barr & Stroud roof binocular used in comparison. 40 years ago, the Zenoptem would have set the average factory worker a whole month’s salary to acquire new. In contrast, the Barr & Stroud Sierra can be had for between £100 and £120 in today’s market.  The value of waterproofing was made manifest in the observation of rusting of some of the metal internal components of the Zeiss. The Sierra, in contrast, is fully waterproof, o-ring sealed and purged with dry nitrogen gas to inhibit internal fogging and corrosion of any metallic components used in its construction.

    Enormous advances in optical technology over the last four decades, particularly full broadband multi-coatings applied to all lens and prism surfaces, higher quality optical glass, as well as phase coated prisms on the roof binocular, collectively allow very efficient light transmissions to the eye. This is all the more remarkable since roof prism designs usually have many more optical components than their porro prism counterparts.

    Better eregonomics in modern roof prism binoculars as well the employment of strong, low mass polycarbonate housings in their design make them lighter and easier to use than their porro prism counterparts from a generation ago. All of these add to the comfort of using them either during the day or at night when looking at the heavens.

    I had a look on ebay to see what these old Jenoptems were being offered for. I found quite a few of them selling for between £150 and £200, so not the high prices demanded by other classic binoculars.

    Like with all optical firms, time has marched on, with modern binoculars offering much better performance than earlier models.

    This comparison test must have implications for many people who already own or use older binoculars and who have not compared them to modern incarnations. And that’s as true for Zeiss as with any other manufacturer. Indeed, I was quite shocked at how much better my first quality roof prism 8 x 42 roof prism binocular fared compared to an old 7x 50 porro I was gifted back in the early 1990s. Technology has well and truly marched on! And while I like classic instruments just as much as the next guy, I see little point in using any when even modest instruments created in the modern age are likely to perform better than similar instruments made a generation ago. It’s just a hard fact of life.

    The technology of the past is certainly interesting but it would be daft to neglect the advances offered in the modern era.

     

    I would like to extend my thanks to Sandy and his parents for allowing me to test drive these old binoculars. I will be advising him to use lens caps on the optics when not in use and have also provided a sachet of silica gel dessicant to minimise moisture-induced corrosion of the optic.

     

    Neil English discusses all manner of classic telescope technology in his 650+ page historical work, Chronicling the Golden Age of Astronomy(Springer-Nature).

     

    De Fideli.