Astronomy with a Pocket Binocular.

Creating a new genre of amateur astronomy literature.

A work commenced November 11, Anno Domini 2019.

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. 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 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.

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 in the mood 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.

 

 

To be continued…………………………………..

 

De Fideli.

In Search of a Good 8 x 32 Binocular.

Two mid-priced 8 x 32 binoculars compared: the Celestron Trailseeker(left) and the Helios LightWing HR( right).

The march of technology continues apace and never ceases to amaze me. This is especially true when it comes to telescope and binocular optics. You can now buy very decent optics at budget prices that display a level of quality we could only dream of a couple of decades ago. And technologies that were only available on premium optics up to fairly recently are now being offered by companies offering much more economical packages to sate the requirements of the masses.

That’s exactly how I feel about my recent foray into binocular testing. Advances in coating technology, in particular, has allowed many new optical firms to offer products that are edging ever closer to the performance levels only available on premium models until recently. Even entry-level roof prism binoculars feature decent anti-reflection coatings on all optical surfaces(which can be as many as 30 in a good roof prism binocular), as well as phase correction technology that significantly increase contrast, accurate colour rendition and image brightness. These less expensive models used either aluminium or silver coatings to boost light transmissions to as high as 80 to 85 per cent, but one can now obtain very economically priced models that also feature super-high reflectivity, broadband dielectric coatings that have increased light transmission to above 90 per cent, in touching distance of the most expensive, premium binoculars money can buy.

Unfortunately, many amateurs who enjoy using quality binoculars mistakenly conflate high-level optical performance with the introduction of extra low dispersion (ED) glass, but the truth is that such an addition contributes little to the quality of the optical experience. Much more significant is the use of higher quality coatings that significantly increase both the brightness and contrast of the images, which in turn enables one to see those finer details, thereby boosting resolution(perhaps this is why the Helios has HR in its name?). Of course, many(but not all) premium binocular manufacturers use a combination of ED glass elements and the finest dielectric coatings, making it all the more difficult for the user to assess the relative importance of either component. But I was able to explore and confirm the dramatic effects of the latter by putting a couple of  mid-priced 8 x 32 compact roof prism binoculars through their paces; a Helios LightWing HR and a Celestron Trailseeker(both pictured above), both of which feature premium quality dielctric coatings on the prism surfaces as well as high-quality broadband anti-reflection coatings on the multiple lenses and prisms used in their construction. Neither instrument contains ED glass elements however. For more on this, check out this short youtube presentation by an experienced glasser and binocular salesman describing one of the models I will be evaluating in this blog(the Helios LightWing),  and who formed the same conclusions as this author.

Both instruments were acquired from the same source, Tring Astronomy Centre. Their friendly and knowledgeable staff have offered exceptional service with a number of past purchases and I had thus no hesitation approaching them again for the acquisition of these 8 x 32 compact binocular models.

The first model I acquired was the Helios LightWing HR 8 x 32, which set me back £127 plus £5 to ensure an expedited delivery of the package within 24 hours of ordering. As soon as it arrived, I inspected the contents, which included the binocular with a rain guard, soft carry case, a lens cloth and generic(read single page instruction sheet) and padded neck strap. Within minutes of its arrival, I had the binocular out of its case to perform my iphone torch test in my living room to see how well an intense beam of white light behaved as it passed through the instrument. As I outlined in a few previous blogs, such a test is extraordinarily sensitive, showing up even the slightest stray reflections in the field of view and revealing how well the optical components suppressed the tendency of the light to diffuse across the field, reducing contrast as it does. Well, to my great relief, the result was excellent! Despite the torch being set at its highest setting in a darkened room, the Helios LightWing HR showed only the feeblest level of ghosting on axis. What is more, there was no difraction spikes or diffused light in the field! The image was exceptionally clean. Indeed, comparing the result to my control binocular, a Barr & Stroud Savannah 8 x 42, which also exhibits exceptional stray light control, the Helios was providing even better results!

To put this in some additional context, the torchlight test result for the Helios 8 x 32 was better than my Zeiss Terra ED 8 x 25 pocket binocular and a Swarovski EL Range 10 x 42, as I recall from my notes!

I now had a new standard by which to measure all other binoculars!

The same was also true when I placed the light beam just outside the field of view. Only a very minimal amount of glare was seen in the field.

The Helios LightWing HR 8x 32 revealed exceptional control of stray light and annoying internal reflections.

Wow!

This told me that the binocular ought to produce very high contrast images in even the most demanding conditions, either by day, glassing in strongly backlit scenes, or at night, when looking at bright light sources, such as artificial street lighting or a bright Moon. No doubt, this is attributed to a variety of factors including excellent multi-layer coatings on all optical surfaces, as well as a sound knowledge of how to adequately baffle the instrument.

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Note to the reader: My pet peeve is seeing excessive glare and strong ghosting from internal reflections in a binocular image. Indeed, I am quite intolerant of it! Moreover, I usually dismiss any reviews that do not test for this phenomenon. Unfortunately, that also entails taking the majority of user reviews I read online with a large dose of salt!

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Examining the Helios, I noted the unusual colour cast of the anti-reflection coatings on both the objective and ocular lenses. They seemed to be immaculately applied! I also noted how the objectives were recessed very deeply; with ~ 10mm of overhang. This is a very good(and often overlooked!) design feature, as it cuts down on peripheral glare during bright daylight observations and also affords considerable protection from dust and rain.

The unusual colour cast of the anti-reflection coatings of the Helios LightWing objective lenses.

Mechanical assessment: The Helios is very well constructed. The chassis is fabricated from a magnesium alloy which combines light weight(500g) with good mechanical strength. This is an unsual offering in such a low-cost instrument, with cheaper polycarbonate or even ABS plastic being the rule rather than the exception on models offered at this price point. The central hinge had enough tension to maintain my particular IPD but I would have liked it to be just a little bit stiffer(just like my wonderful Barr & Stroud Savannah 8 x 42). I found handling the binocular to be unusually tricky, as the rubber eyes needed to attach the neckstrap protrude from the barrels a little too much, making it rather more awkward to get the binocular comfortably placed in my hands while observing.

The focus wheel is very large in relation to the overall size of the instrument. Indeed, I thought it was a little too large! Although I could get a good grip, rotating it showed that it was somewhat clunky and offered unusual resistance to movement. In contrast, the dioptre ring moved with silky smoothness, and you can actually see the right ocular field lens moving as you rotate it!

The buttery smooth right-barrel dioptre ring is a joy to adjust.

The eyecups are rather stiff but do extend upwards with two clickstops. With an eye relief of 15.6mm, eyeglass wearers will find it difficult to image the entire field. Fortunately for me though, this wasn’t a problem, as I don’t wear eye glasses while glassing. The cups are made from quality metal covered by a soft rubber-like material. They are very firm and hold their positions securely even when undue pressure is applied to them. Overall, a very nice touch!

The chassis is covered by a rather thin rubberised skin, which was somewhat thinner than I’ve seen on a variety of other binoculars I’ve sampled. As a result, it has slightly less friction while man handling, which can prove important, especially if used for prolonged periods in the field. It also means that it would wear down that little bit faster after extended use.

The Helios can be attached to a tripod or monopod for increased stability via the built-in bush located between the barrels, toward the front of the instrument.

Optical daylight testing: Scanning some autumn leaves in my back garden confirmed what I had witnessed in the torchlight test. The image was very bright and tack sharp with wonderful contrast and colour fidelity. There was nary a trace of chromatic aberration( which continues to affirm my belief that ED glass is unnecessary: -a marketing gimmick? – for such small, low power binoculars). However, this was only true in the central 50 per cent of the field. The outer part of the field became progressively softer with the edge being out of focus. Examining a telephone pole about 25 yards in the distance unveiled very strong field curvature as it was moved from the centre to the edge of the field of view.

I hit another snag when I attempted to image the Fintry hills about a mile in the distance. The focus wheel was racked to the end of its natural focus travel but I still could not quite reach a sharp focus. Adjusting the dioptre ring on the right barrel allowed me to just get there but the left barrel was still not sharply focused. After dark, I did a test on the bright star Vega, which unfortunately confirmed my daylight tests. Although I could achieve pinpoint sharp images in the right barrel, the left barrel showed that the star was badly bloated. Another test on the Moon showed the same thing. The right barrel gave a razor sharp image with exceptional contrast and no internal reflections or diffused light around it, but the image at the edge was badly out of focus.

The whole experience left me somewhat bewildered. Why expend so much effort into applying state-of-the art coatings into a binocular with nice mechanical features, only to see excessive field curvature in the outer part of the field? It just didn’t make sense! I mean, Helios could have made the field a little smaller(it has a true field of 7.8 degrees) with sharper edge definition and I would have been happy.  In reallity you see, I had been spoiled by the nearly flat fields presented by my Barr & Stroud Savannah 8 x 42(and over a larger field to boot- 8.2 degrees), as well as those presented by my Zeiss Terra pocket and my other models with aspherical ocular lenses. Needless to say I was disappointed and decided to contact the staff at Tring the same evening, explaining my findings.

Next morning, they contacted me, apologising for the defective optic, as well as suggesting that I could have a replacement Helios LightWing, or try a Celestron Trailseeker 8 x 32, which apparently had very similar specifications to the former. Now, I had a bad experience with an 8 x 25 Celestron Nature DX(an entry-level roof prism binocular) which showed far too much glare and internal reflections for my liking. But I had a good look at the specifications on the Celestron Trailseeker models, which were recently discounted by 20 per cent and were now being offered at the same price as I had paid for the Helios LightWing. After some deliberation, I decided to accept their offer of trying the Trailseeker. And to their credit, Tring shipped out the binocular, together with a return label for the Helios, the same day, and I received it less than 24 hours later!

How about that for customer service!

The Celestron Trailseeker 8 x 32 package.

With some trepidation, I opened the package and inspected its contents. First impressions looked good. I received the binocular, a much higher quality carry case, a binocular harness, tethered rubber objective caps and rain guard, a decent quality padded neck strap, a lens cleaning cloth and a comprehensive instruction manual dedicated to the Trailseeker  line of binoculars( in five languages).

The Trailseeker binocular specifications looked very similar to the Helios, which included the application of premium-quality phase and dielectric coatings, a 7.8 degree field (136m @1000m), Bak-4 prisms, o-ring sealed, dry nitrogen purged, making it fog proof and water proof(though to what extent was not revealed). And just like the Helios, the Trailseeker can be mounted on a tripod or monopod.

As with the Helios, the Trailseeker has very deeply recessed objectives (again about 10mm) but the anti-reflection coatings looked different in daylight;

The Trailseeker also has deeply recessed objective lenses but the coatings appeared different.

Just like the Helios, the Celestron Trailseeker has a rugged magnesium alloy chassis but the focus wheel is significantly smaller. Weighing in at just 450g, it is 50g less bulky than the Helios. The Trailseeker build quality is excellent; rugged, much easier to handle than the Helios and overall having better ergonomics. The tough, rubberised covering has better grip than the Helios too, and small thumb indentations on the belly of the instrument makes it that little bit more comfortable to hold in the hand.

Nicely placed thumb indents on the underside of the Trailseeker make handling that little bit more intuitive.

Well, you can guess what I did next; yep, I set up my iphone torch, turned it up to its brightest setting and placed it in the corner of my living room with the curtains pulled to cut off much of the daylight. With a good close focus of about 6.5 feet, eagerly I aimed the Trailseeker binocular at the light and examined the image.

Drum roll……………………………………….

An excellent result! Internal reflections were minimal, diffused glare was all but absent and diffraction spikes were very subdued. Comparing the Trailseeker to my Barr & Stroud Savannah 8x 42 control binocular showed that it was on par with it. What a relief! To be honest, I had some reservations about the Celestron, owing to my unfavourable experience with the cheaper Nature DX model, and so I half expected that they might skimp on this important process. But no, they did a very good job! So far, so very good!

I was also impressed with the mechanical attributes of the Trailseeker, which is difficult to ascertain vicariously without man handling it. Though quite conservative in design, the eyecups are of high quality(metal over rubber) but have a nice feel about them. They twist up much more easily than those on the Helios and have two settings. Like the Helios, the eye relief is pretty tight(15.6mm) for eye glass wearers but is plenty good enough for those who observe without glasses.They do not budge even when considerable force is applied to them. I would rate their quality as very high, so much so that I don’t think I will have much in the way of problems with them going forward.

The metal-over rubber eyecups of the Celestron Trailseeker are a good step up from the Nature DX models and feel very secure while glassing.

The focus wheel has a ‘plasticky’ feel about it but unlike the Helios, infinity focus does not lie at the extreme end of the focus travel. This is actually useful for ‘focusing out’ some of the aberrations at the extreme edge of the field. Unlike other user reviews of the Trailseeker, the focus wheel on the unit I received was quite stiff to operate out of the box but this will surely loosen up with more use. Rotating the focuser both clockwise and anti-clockwise revealed little or no backlash or bumpy spots that you often encounter on cheaper binoculars. Some users balk at the idea of using a plastic focuser but I cannot for the life of me understand why it would make much difference. I mean, if it works, it works! What’s to give?

The focus wheel on the Trailseeker is nothing out of the ordinary but does work well in field use.

The dioptre ring is located under the right eyecup. It rotates smoothly with just the right amount of friction.

Optical daylight testing: As I’ve illustrated above, good mechanical design and great control of stray light don’t count for much if the images don’t deliver. So I was eager to see how the Celestron Trailseeker behaved when looking ’round the landscape. Accordingly, I examined the same autumn leaves in my back garden set a few tens of yards away. This time, the results were very much more encouraging! The leaves focused beautifully, throwing up excellent brightness, contrast and sharpness with a much wider sweet spot than in the Helios, which I estimated to be about 70 per cent of the field.  I could immediately tell that there was much less field curvature in this binocular than in the Helios, allowing me to sharpen up the edge of field definition with only minor tweaking of the focus. This much reduced field curvature was also apparent when I examined the same telephone poll I observed with the Helios. Instead of the strong off-axis distortions I encountered with that instrument, as the pole was moved from the centre to the periphery of the field, the Trailseeker proved much more forgiving.

What a relief!

Having said all of this, there was more off-axis field curvature in the Trailseeker than in my Barr & Stroud Savannah 8 x 42, which, in comparison, throws up a wider and flatter field nearly all the way to the edge. As I’ve said many times before, the Savannah is a phenomenal operator given its very modest price tag. Perhaps some of the drooling gayponauts reading this blog right now could get off their fat backsides and confirm it!

Nah, probably too much to ask!

The Barr & Stroud Savannah 8 x 42 wide-angle binocular; an existential threat to the hubris of thieving gayponauts.

Nightime testing:

After dark, the Trailseeker delivered excellent results on artificial street lights, just as my torchlight tests reliably anticipated. There was no annoying glare, internal reflections and the diffraction spikes were small and very subdued. Turning the instrument on a low Moon skirting the horizon showed wonderful sharpness on axis, with well above average contrast. And when I placed the Moon at the edge of the field, it remained quite sharp, though visibly softened by a small amount of field curvature. Needless to say, it was in a completely different league to the Helios in this regard!

Later in the night, with the Moon having set, I examined the appearance of the large and sprawling Alpha Persei Association located nearly overhead at the time. This provided an excellent test of how its many bright stellar members would behave from the centre of the binocular field to the field stop. To my relief, the stars remained acceptably small and sharp across the entire field, with the stars at the edge of the field requiring only a small tweak in focus to improve their definition. They did not balloon to stupidly large sizes like I observed in the Helios.

Turning the binocular on the Hyades in Taurus gave very pleasing results too. Contrast was excellent with its many colourful stellar components remaining acceptably small and crisp even at the edges of the field.

I considered these results to be very acceptable. This is one small binocular that can be used profitably for nightime observations!

A Walk in the Countryside with the Celestron Trailseeker 8 x 32

Although the Celestron Trailseeker 8 x 32 is a small, high-quality and lightweight instrument, it is not readily pocketable, unless you have a coat that has rather large and deep receptacles. Having tried a few 8 x 32 binoculars, I personally find them a little awkward to use in comparison to my two favourite pocket binoculars like my Opticron Aspheric LE and my Zeiss Terra(both of which are 8 x 25 formats) or a larger instrument such as my 8 x 42. I just find the 8 x 32 format a bit kludgy in my rather small hands. That said, the 8 x 32 seems to be a popular choice for birders and other nature enthusiasts, who tire of schlepping around a larger instrument for hours on end. In good light, there’s no real advantage in using a larger format binocular and so I tend to use my pocket binos most often. But if you are observing in low light conditions, such as a dull, overcast winter day, late in the evening or early in the morning, the 8 x 32 would definitely be a better choice. I have verified this wisdom by comparing the views through my  8 x 25 Terra and the 8 x 32 Trailseeker at dusk, where the brighter images served up by the latter are plainly in evidence. And because you have a relative abundance of good quality light to play with, you can see more details in the image. Shimples!

Choosing a small binocular is a deeply personal choice that you can only decide on after trying them in the field.

The consensus view is that larger binoculars are more comfortable to use since their larger ocular lenses make it easier to place your eyes in the correct position to see and immerse yourself in the field of view. I believe there is definitely some truth in this, but in the end it’s really about what you get used to. I personally have no trouble lining up my eyes with the smaller eye lenses on my pocket binos, so I never see this as being much of an issue.

Enjoying the rich colours of autumn on a hill walk overlooking Fintry.

All that having been said, the Trailseeker 8 x 32 is a very handy companion on my daily two-mile ramble ’round Culcreuch Castle Estate, which has some extensive wooded areas, a fast-flowing river, numerous small brooks, open fields which extend towards the surrounding hills and a small pond, where I enjoy watching the antics of a variety of water-loving avian species. The field of view is very generous at 7.8 degrees, which is quite large as most 8 x 32 binoculars go, though some models sport still larger fields in excess of 8( ~ >140m@1000m) angular degrees. The razor sharp optics on the Trailseeker has given me many wonderful views of golden autumn leaves glistening in weak November sunshine. I especially love to stand under a tree and glass the branches above me, focusing in on their wondrously complex contours. The low autumn Sun this time of year illumines the trunks of the trees in the wooded areas around the estate, highlighting the wonderful texture of the tree bark and the play of light upon the lichens and mosses that live symbiotically with it.

If time is not against me, sometimes I like to stop and focus in on a stretch of water flowing from the numerous small streams that feed into the Endrick, imaging the contours of rocks laden with fallen leaves and closing in on the foamy organic bubbles that swarm along the fast-flowing stretches. And when the Sun shines on the water, I can feast my eyes on the beautiful and intense reflections emanating from its surface. This is where glare control is paramount, as even a small amount of light leakage can ruin an otherwise compelling binocular scene.

Binoculars have come a very long way since their founding days. I find it amazing that one can acquire quality optics and durable mechanics like this at such keen prices. The Celestron Trailseeker 8 x 32 has been a very pleasant surprise, combining wonderful ergonomics with state-of-the-art optical science. I think a lot of people will enjoy it.  And now that its price has come down significantly, this is a good time to grab yourself a real bargain and enjoy the wonders of nature up close and deeply personal.

Just in case……………..

 

Thanks for reading!

 

Neil English has fallen in love with what binoculars have revealed to him, and is seriously thinking of compiling a larger portfolio of  binocular experiences for a future book-length treatise on their various applications.

 

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

 

US Supreme Court Overules Calls by Militant Atheists to Demolish a World War I 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

 

Overwhelming Financial Response for Israel Folau’s Unlawful Dismissal by Rugby Australia

 

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

 

Amazonia Burning: Facts Versus Media Speculation

 

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

 

Portrait of a Second-Rate Barnacle Collector

 

Revelation: Number of Transgender People Seeking Sex Reversals Skyrockets

 

Chasing the Darwinistas out of Town

 

Climate Change: Tempering Media Hysteria with Facts

 

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

 

Adam & Eve: Redux

 

Encyclopedia Galactica

 

Phillip E. Johnson: A Tribute

 

The Poison of Humanism

“The Valley of Vision:” a Brief Commentary.

“The Valley of Vision;” a Collection of Puritan Prayers & Devotions, Arthur Bennett(ed.)

I’m new to books of prayer. For many years, I never really saw the point of them. I mean, why would one benefit from reciting or quietly reading the prayers written down by others? Shouldn’t one earnestly seek God with one’s own words or thoughts? Wouldn’t it be the case that using the collected spiritual thoughts of others is merely cheating? It was reasoning along this line that held me back from using anything other than the Bible to seek inspirational material for an active prayer life. I”ve never really been that keen on reading the works of other Christian authors for fear that I might be led astray by false doctrines and distortions of the true message of the Gospel. Goodness knows how many books published in recent times have apparently run roughshod over the true message of hope contained in the pages of the Holy Book.

So, it was with some trepidation that I decided to bite the bullet and order a copy of a little prayer book called, The Valley of Vision, compiled by the late Reverend Arthur Bennett(1915-1994), an English Christian evangelist, who dedicated his life to shepherding a flock of fellow Christians in the various places he settled during his long and fruitful life.

A Brief Biography

Arthur was born on May 15 1915, in the South Yorkshire town of Rochester, as the First World War raged across Europe. The family had moved a few times in search of a higher standard of living, spending some time in Cudworth before finally settling in Barnsley, South Yorkshire. The son of a barber, Arthur left school at the age of 14 where he took up a job as a “lather boy” in his father’s establishment. It was around this time that Arthur joined the local Salvation Army and one day, so his biographers inform us, while he was was walking though the citadel, he heard the sound of singing and people giving praise to God in the town hall. He entered and was welcomed by the congregation. The event stirred him and that same evening he resolved to give his life to Christ.

During his late teens, Bennett joined the Church of England and travelled to London to train as an evangelist, working among the poor of the city. By the time he reached his early twenties, Arthur was assigned to a number of villages spread across East Anglia, where he would travel from place to place in a horse-drawn cart. While assigned to the village of Elmsett, Suffolk, he met the love of his life, Margarette Jones, who was also a Bible teacher, and the couple were married in Margarette’s home town at Carmarthenshire, South Wales, on August 26, 1942.  By then, Arthur had almost completed his studies at Bristol’s Clifton Theological College, shortly after which he was ordained as a minister in the Chuch of England. He accepted his first post as curate at Woodhouse, Huddersfield, where the couple remained until 1949, when he was then appointed Vicar of Christ Church, Ware, Hertfordshire. And in 1956, Bennet, his wife and five children moved to St. Paul’s Church, at St. Albans, Hertfordshire, where they lived for the next eight years.  In the mid 1960s, Bennett accepted an invitation to shepherd a few parishes in the catchment area of Ware, Hertfordshire, where he settled into 17 years of Bible teaching and preaching. After 39 years of active ministry, Bennet retired to Clapham, Bedfordshire, and after a short illness passed away in 1994, where he was laid to rest in the Churchyard of Little Munden, Hertfordshire. His wife, Margarette, survived him a few more years before breathing her last in 1997.

Interest Piqued in Puritan Spirituality

From his early youth, Bennett cultivated a keen interest in Church history, and in particular, the early Puritan movement, which began as an ecclesia within the Church of England in the late 16th century. Bennett was drawn to the simple spirituality of Puritan thinking, studying the available archives of their literature which had done much to disseminate the Good News far beyond the shores of England, but especially so in Colonial North America. Drawing on his diligent studies conducted throughout his career, Bennett set himself the task of compiling a collection of prayers from the founding fathers of Puritan spirituality, dating from the closing years of the 16th century right up to the late 19th century. Although he authored several important books on similar themes, Arthur Bennett is best known for his little book of Puritan prayer, The Valley of Vision, which was first published in 1975 by The Banner of Truth Trust.

At first sales of the work were slow, culminating with about 20,000 copies of The Valley Of Vision sold by the time Bennett passed away in 1994, but in the time since, the estimated number of copies of the work in the hands of Christians rose rapidly to over 350,000 copies distrubted around the world.  I have a strong preference for the printed word. My copy is the small, bonded leather edition representing the 18th re-print as of 2018 (405 pages, £19 UK) You can also get a sense of the kind of spiritual exercises in the book by having a look at the first 14 pages which is presented in PDF format here.

Contributors & Content

As explained in the preface to the work, Bennett drew on an eclectic mix of prayers and devotions of some of the more prominent members of the Puritan movement dating mostly from the 16th through 18th centuries, which include:

  • Thomas Shepard (1605-1649)
  • Richard Baxter (1615-1691)
  • Thomas Watson (c. 1620-1686)
  • John Bunyan (1628-1688)
  • Isaac Watts(1674-1748)

 

  • Philip Doddridge (1702-1751)
  • William Romaine (1714-1795)
  • William Williams [of Pontycelyn] (1717-1791)
  • David Brainerd (1718-1747)
  • Augustus Toplady (1740-1778)                                                                                                                                                                                                                              It also includes a small number of prayers composed by those attracted to Puritan spirituality in the 19th century including:
  • Christmas Evans (1766-1838)
  • William Jay (1769-1853)
  • Henry Law (1797-1884)
  • Charles Haddon Spurgeon (1834-1892), widely considered to be the last of the great Puritans.

 

The opening prayer, called The Valley Of Vision, was written by Bennett himself, the title of which was inspired by a reading of Isaiah 22( KJV emphasis);

Lord, high and holy, meek and lowly,

Thou hast brought me to the valley of vision,

where I live in the depths but see thee in the heights;

hemmed in by mountains of sin I behold thy glory.

Let me learn by paradox

that the way down is the way up,

that to be low is to be high,

that the broken heart is the healed heart,

that the contrite spirit is the rejoicing spirit,

that the repenting soul is the victorious soul,

that to have nothing is to possess all,

that to bear the cross is to wear the crown,

that to give is to receive,

that the valley is the place of vision.

Lord, in the daytime stars can be seen from deepest wells,

and the deeper the wells the brighter thy stars shine;

Let me find thy light in my darkness,

thy life in my death,

thy joy in my sorrow,

thy grace in my sin,

thy riches in my poverty

thy glory in my valley.

All of the prayers derived from the Puritan writers are approximately the same length as Bennett’s opening devotion, and for convenience are divided up into very useful sub-sections so that the reader can concentrate on different themes, which include:

1. Father, Son and Holy Spirit

2. Redemption and Reconcilaition

3. Penitance and Deprecation

4. Needs and Devotions

5. Holy Aspirations

6. Approach to God

7.Gifts of Grace

8. Service and Ministry

9. Valediction

10. A Week’s Shared Prayers

Even a cursory reading of the book will show that all the Puritan authors were deeply committed to the Scriptures, with no turning to the right or to the left, as it were. These were holy men, who considered all of creation sacred, and who poured out their innermost thoughts to their Creator, witholding nothing. In my mind’s eye, I see those prayers billowing upwards, headlong toward the mercy seat of God, where the Scriptures inform us that they are collected in vials(Revelation 5:8).

In all, some 196 prayers are presented, but Bennett does not reveal the individual authors of those prayers.

I have many favourites to draw on. Here’s an excerpt from Section I; Father Son and Holy Spirit; from a prayer entitled: Man’s Great End:

Lord of All Being,

There is one thing that deserves my greatest care,

that calls forth my ardent desires,

That is, that I may answer the great end for which I am made-

to glorify thee who hast given me being,

and to do all the good I can for my fellow men;

Verily, life is not worth having

if it be not improved for this noble purpose.

Yet, Lord, how little is this the thought of Mankind!

Most men seem to live for themselves,

without much or any regard for thy glory,

or for the good of others;

They earnestly desire and eagerly pursue

the riches, honours, pleasures of this life,

as if they supposed that wealth, greatness, merriment,

could make their immortal souls happy;

But alas, what false delusive dreams are these!

pp 22

Some of the prayers brought an instant smile to my face. How about this opener(under Sins) for efficiency?

Merciful Lord,

Pardon all my sins of this day, week, year,

all the sins of my life,

sins of early, middle, and advanced years,

of omission and commission….. pp 158

 

Say no more eh? That’s right! Our God forgives all sins; past, present and future.

Others are altogether more sonorous. Take this excerpt, taken from a prayer entitled, Union with Christ;

O Father,

Thou hast made man for the glory of thyself,

and when not an instrument of that glory,

he is a thing of nought;

No sin is greater than the sin of unbelief,

for if union with Christ is the greatest good,

unbelief is the greatest sin.. pp 36

Unbelief is portrayed as sin, and not only that; it is ” the greatest sin.” And where might one find support for that position in the Scriptures? Well, for a start, how about the tract from Hebrews:

But without faith it is impossible to please him: for he that cometh to God must believe that he is, and that he is a rewarder of them that diligently seek him.

Hebrews 11:6

Unbelief is rebellion, anarchy of the heart, a conscious decision to reject the authority of our Creator over our lives. Hebrews 3 reminds us:

Take heed, brethren, lest there be in any of you an evil heart of unbelief, in departing from the living God.  But exhort one another daily, while it is called To day; lest any of you be hardened through the deceitfulness of sin.  For we are made partakers of Christ, if we hold the beginning of our confidence stedfast unto the end;  while it is said, To day if ye will hear his voice, harden not your hearts, as in the provocation.  For some, when they had heard, did provoke: howbeit not all that came out of Egypt by Moses.  But with whom was he grieved forty years? was it not with them that had sinned, whose carcases fell in the wilderness? And to whom sware he that they should not enter into his rest, but to them that believed not?  So we see that they could not enter in because of unbelief.

Hebrews 3:12-19

So, simply put, those without faith will not enter His rest.

So much for Universalism!

The bonded leather edition is printed on high quality paper with little bleed-through. The pages have a lovely gold gilding and a single black ribbon marker. Each prayer only takes just a couple of minutes to read.

There are many eclectic topics discussed in the prayers chosen by Bennett. One prayer I especially liked is found in the Service and Ministry section and gives thanks to the Lord for giving us His precious Word. Called the Minister’s Bible, here’s an excerpt:

O God of Truth,

I thank thee for the holy Scriptures,

their precepts, promises, directions, light,

In them do I learn more of Christ,

be enabled to retain his truth,

and have grace to follow it.

Help me to lift up the gates of my soul that he may come in

and show me himself when I search the Scriptures,

for I have no lines to fathom its depths,

no wings to soar to its heights.

By his aid may I be enabled to explore all its truths,

love them with all my heart,

embrace them with all my power, engraft them into my life. pp 346

In this ephemeral world we live in, with its endless distractions and technological marvels, reading the Bible every day has become as important to me as eating, exercising and washing. It has become a constant comfort to read and re-read in the quiet of the morning and in the evening; to meditate on its precepts and absorb its spiritual wisdom that is older than nature herself.

Many of the Puritan authors demonstrate an acute awareness of sin, and the utter inadequacy of trying to achieve salvation by one’s own efforts(Ephesians 2:8-9). You can sense a great desire of many of the contributors to go home, to be eternally re-united with their Creator in Paradise.  In the Valediction section, for example, we read this prayer, entitled Earth And Heaven;

O Lord,

I live here as a fish in a vessel of water,

only enough to keep me alive,

but in heaven I shall swim in the ocean.

Here I have a little air in me to keep me breathing,

but there I shall have sweet and fresh gales;

Here I have a beam of sun to lighten my darkness,

a warm ray to keep me from freezing;

yonder I shall live in light and warmth forever.

My natural desires are corrupt and misguided,

and it is thy mercy to destroy them;

My spiritual longings are of thy planting,

and thou wilt water and increase them;

Quicken my hunger and thirst after the realm above  pp 370

 

The Valley of Vision is a great resource for those who have committed themselves to a Christian path through this present evil age. Every day, we edge closer to our eternal home(Hebrews 13:14), where we will serve the Lord with purity of heart.  And though I was sceptical about whether any prayer book would do anything to enrich my prayer life, I must admit to have been badly mistaken. There is so much richness in the pages of this little classic prayer book, treasures that can transform the inner groanings of the soul into beautiful, deep and expressive worship.

And that’s why I would unhesitatingly recommend it to the faithful.

Natural companions.

 

Thanks for reading!

 

 

De Fideli.

On the Campaign Trail: Again!

Image result for Roman battle Gladiator images

I decided to go on campaign again over the weekend of October 26/27 2019. This time it was in response to a provocatively titled post by a guy I helped secure a book contract for some time ago. The thread in question was entitled,  Evolution tells us we might be the only intelligent life in the universe.

While I agreed with the conclusion, I took issue with the mechanism, or rather the lack of a mechanism implied by the poster; Darwinian evolution. I responded by posting a number of links to the conclusions drawn from an expert in the fossil record, Dr. Gunter Bechly, who defected from neo-Darwinism to join the intelligent design movement, based on the enormous body of new evidence that shows no intelligible Darwinian progression. Despite this data being freely available for over a year now, the poster seemed to reveal a complete ignorance of the true status of this failed ideology masquerading as science.

I reinforced Bechly’s talk with a number of other short, supplementary links, explaining in simple terms, how neo-Darwinism has now been disproven and is no longer tenable as an explanation for the origin of biological systems:

How has Neodarwinism been disproven?

What is the waiting time dilemma and how does it refute Neodarwinian evolution?

How does the evolution of whales present a challenge to Neodarwinism?

Most of the earlier posters digressed into discussions more along these lines than anything else; wishy-washy New Age dribble.

As expected, the exchanges garnered a substantial number of viewers, growing from about 800 to ~1600 hits in the space of 24 hours. Like I explained in earlier campaigns, folk have a bizarre attraction to conflict. They just can’t help themselves it seems! I got the usual emotive and hostile response from predatory trolls, who hurled abuse at me, but never discussed the factual content of those links. One person responded positively in my defence, but stated that he was neither religious(nor am I for that matter, as Christianity is not a religion but a relationship) nor an endorser of intelligent design. That’s all well and good, but he couldn’t proffer an alternative naturalistic explanation. My question to that person is: if it’s not Darwinian evolution, how does one best explain the 18+ big bangs that have occurred throughout the long history of life?
I believe that the answer is that new information from an outside source was required to bring about those changes in the fossil record. And that information provider was the God of the Bible.
The same chap who came to my defence asked why I believe humanity is alone in the cosmos? Why wouldn’t an intelligent designer like the Lord God Almighty not create other civilizations? Some of my reasoning comes from the general observation that every where(apart from Earth) we look in the cosmos, conditions appear to be hostile toward life. I provided those scientific details in my debut feature article for Salvo Magazine Volume 50(fall 2019 issue). Although I was not at liberty to discuss the theological reasoning behind my conclusions on such a forum, I think one reason is grounded in a kind of pagan idolatory. I see these mythical advanced civilizations as a distraction from our true duty to look out for and help one another and to responsibly steward all other life on this jewel planet we live on. Like I said before, the only aliens we are ever going to meet are our neighbours!  This talk by Dr. John Barnett fleshes out still more theological reasons why I do not believe in the existence of ETI.
In summary, I view this latest online campaign against general scientific ignorance as a success. It is my fondest hope that some people who read that thread will come to a knowledge of the truth.
Sincerely,
Neil English PhD.
Postscriptum: Once again, I got physically sick(I threw up) after the thread linked to above was locked.The same thing happened in the aftermath of my last campaign.

 

 

Return to Wigtown: October 2019.

The driveway up to East Kirkland Farm, Wigtown.

Our annual family October vacation almost never happened this year. Our car gave up the ghost, necessitating the purchase of a new one just a week before our planned trip, and then, to add insult to injury, our fan oven died, requiring us to pay out still more cash to get it replaced. Luckily, I had just received an advance on my new book, as well as my first pay cheque for my debut feature-length article in Salvo Magazine, outlining the scientific case against extraterrestrial life.  Unfortunately, the holiday cottages at East Kirkland Farm were almost fully booked by the time we made our enquiries, and all the proprietors could offer us was a few days, starting on Wednesday October 16 until the end of the week. Trying to salvage some quality time away, we jumped at the chance and decided to go for it!

This was our fourth trip down to Wigtown, located at the very southwest tip of Scotland. As I have documented in previous blogs, I have enjoyed some beautiful, pristine skies here in the past, using a variety of hand-held binoculars and telescopes . What I mainly wish to report here is one night of observations, which took place at East Kirkland on Wednesday, October 16 2019.

I took along my trusty, high-performance 130mm F/5 travel Newtonian reflector in its padded aluminium case and my new pocket binocular; a Zeiss Terra ED pocket 8 x 25mm, for daylight observations of the landscape. I elected not to take my larger binoculars as there was a bright, nearly full Moon in the sky, which would rise early in the evening making observations with larger binoculars almost impossible to conduct. No, I would be using the Newtonian to carry out some observations of a suite of double stars, both easy and some more challenging, as these are largely unaffected by the presence of a bright Moon.

Two wonderful travelling companions.

After driving through an active weather system in the morning, the skies cleared as we approached Wigtown and the afternoon turned out to be sunny and reasonably warm, with only a few clouds in the sky.  After unpacking, I set up the 130mm on my old Vixen Porta II alt-azimuth mount in the shade of a garden tree where I was able to enjoy wonderful, ultra-high-powered views of the hinterland. As I expained in previous blogs, this little Newtonian is an excellent spotting ‘scope, possessing  superior light grasp and constrast that easily exceeds the performance of conventional spotting ‘scopes that often cost considerably more. This is especially apparent in low light conditions that are all too common during the shorter days of late autumn and winter.  Alas, I didn’t bring along my Vixen erecting lens but I didn’t really need it. I just drank up the views at 118x of tree trunks and branches, golden autumn leaves and bramble bushes, still drenched by the rainfall that occurred that same morning,  just a few tens of yards away in the distance. Indeed, of all the kinds of optical equipment now availalble to the nature lover, conventional spotting ‘scopes make little sense to me. Why fork out so much for an instrument that is severely limited by its small (70-100mm) aperture?

Plotina, my wonderful 130mm f/5 travel Newtonian delivering some ultra-high powers of the terrestrial creation on the afternoon of October 16, 2019.

The evening remained largely cloud free but I knew that a nearly full Moon would be rising early in the east, at about 7.30pm local time. Conditions were quite different to the other occasions I have observed here in past journeys. This time, there was hardly any wind all day and the evening brought some high altitude cirrus cloud and lower altitude cumulus that came and went as the evening dragged on. Still, a quick look at Delta Cygni showed that conditions were, once again, excellent(Ant I-II). The faint companion was steadily seen and observed at 354x (Meade Series 5000 UWA coupled to a 3x Meade achromatic Barlow). The Airy disks were tiny and round with a single, delicate diffraction ring surrounding the bright primary.

Moonrise over Wigtown, as captured at 20:58 h on Wednesday October 16, 2019.

During our summer trip to Pembrokeshire, South Wales, I forgot to bring my flexi-dew shield, which forced me to adopt a totally different strategy while observing. Thankfully, the dew shield came with me this time and it proved indispensable as these calm conditions would bring a heavy dew.

I really got stuck in after supper, just after 8pm local time, visiting a suite of favourite double and multiple stars witth Plotina. Albireo in Cygnus was mesmerizing with lovely calm Airy disks displaying their true colours(the reflector afterall is a true achromatic telescope) in the telescope at 118x. Moving over to Mu Cygni, I cranked up the power to 354x to cleanly resolve the two close companions and a bright field star wide away. Moving into Lyra, I got a text-book perfect split of the four components of Epsilon 1 & 2 Lyrae at 118x but an altogether more satisfying split at 270x (4.8 mm T1 Nagler coupled to a 2x Orion Shorty Barlow) . And to give the reader an idea of how good the skies were here at this time, I was able to cleanly split Epsilon Bootis at 118x and 135x, even though it was very low in the western sky at the time of observation!

Moving to the southwest sky, I turned the little Newtonian on Pi Aquliae and was rewarded by a very crisp splitting of this near-equal brightness pair at 354x. I then moved the telescope on Polaris, the pole star and enjoyed a lovely calm view of its very faint companion at 118x. The same was true of Mizar & Alcor, which  presented a downright dazzling light show in the telescope at 118x.

By 9pm, Cassiopeia was well positioned high in the sky and I turned the telescope to another system, that up to relatively recently was considered tricky by dyed in the wool refractor nuts. I speak of course of Iota Cassiopeiae, which was easily resolved into its three components at 118x. The view was far more compelling at 354x though! From there, I panned the telescope across to Eta Cassiopeiae, where the telescope presented a beautiful, ruddy primary and yellow secondary some three magnitudes fainter(magnitude +7.5)

At about 9.30pm local time, I turned the telescope on another autumn favourite; Almach; which presented gloriously with its orange and bluish components in the Newtonian at 118x and 354x. Finally, I tracked down another very close system, 36 Andromedae, a 1.0″ near equal brightness pair. Centring it in the field of view using the slow motion controls on the Vixen Porta II mount, I cranked up the power to 354x to behold a wonderful sight; two tiny Airy disks with a sliver of dark sky between the components! Reaching for the 4.8mm Nagler, and coupling it to my 3x achromatic Barlow lens, the power was increased to 405x, where I was still able to stably hold both components as they raced across the field of view from east to west.

Some folk might form the erroneous view that these conditions must be rare in the British Isles, but I have conclusively de-bunked that opinion(promulgated by lazy, arm-chair amateurs unwilling to do any field work of this nature). There are, in fact, many places in Britain and Ireland which give the same kind of excellent performance with this little Newtonian reflector. So, it has nothing to do with sheer dumb luck, but all to do with diligent enquiry!

The next day, October 17, proved a washout, unfortunately. Frequent heavy showers of rain put a severe dampener on the vacation and these showers persisted right into the early and late evening, so I didn’t bother to use the telescope. That said, I have one additional memorable observation to report during the wee small hours of October 18. Sticking my head out of doors at 1.20 am local time showed a bright waxing Gibbous Moon skirting very close to the bright star, Aldebaran. Reaching for my little Zeiss Terra pocket binocular showed me a most arresting sight! The Moon was just a few degrees directly east of the horns of Taurus, looking for all the world as if it were about to lock horns with the celestial bull. I watched in sheer amazement as some clouds blew across the Moon from west to east, blotting out some of the glory of the stars of the Hyades, but in the process, creating a wonderful display of light and colour, as the low-altitude rain clouds approached and then receded from our bright, natural satellite. I only wished I had brought along my 8 x 42 Savannah binocular to capture still brighter images of this marvellous apparition, but hindsight is indeed a wonderful thing!

It would have been nice to have another night to accumulate more data at this site but it was not to be. Still, it was good to get away, if only for a few days.

A capital grab ‘n’ go telescope. Powered by human muscle, eyes and brains.

I would continue to encourage others who have a small Newtonian telescope like this to perform their own field tests on these and other double stars. I mean, it’s all very easy to falsify, isn’t it? You just need to collimate accurately and allow enough time for the telescope to acclimate fully to the outside air. That said, If time is against you,  it’s best to start with the easiest pairs and move onto the tighter ones as the telescope nears full equilibration.

Good luck with your adventures!

Neil English is the author of seven  books. His largest work, Chronicling the Golden Age of Astronomy, provides a historical overview of many astronomers from yesteryear who used Newtonian reflectors productively in their exploration of the heavens.

 

De Fideli.

What I’m Reading.

“Escaping the Beginning? Confronting Challenges to the Universe’s Origin.

Did the universe have a beginning—or has it existed forever?

If the universe began to exist, then the implications are profound. Perhaps that’s why some insist it has existed forever.

In Escaping the Beginning?, astrophysicist and Christian apologist Jeff Zweerink thoughtfully examines the most prevalent eternal-universe theories—quantum gravity, the steady state model, the oscillating universe, and the increasingly popular multiverse. Using a clear and concise approach informed by the latest discoveries, Zweerink investigates the scientific viability of each theory, addresses common questions about them, and then focuses on perhaps the most pressing question for believers and skeptics alike: If the evidence continues to affirm the beginning, what does that imply about the existence of a Beginner?

About the Author: Jeff Zweerink (PhD, Iowa State University) is an astrophysicist specializing in gamma-ray astrophysics. He serves as a senior research scholar at Reasons to Believe and as a part-time project scientist at UCLA. He has coauthored more than 30 papers in peer-reviewed journals and numerous conference proceedings.

 

Some Reviews Thus Far Garnered:

“In Escaping the Beginning? Jeff Zweerink leads the reader through a fascinating tour of the scientific development of the big bang theory as well as the theological and philosophical implications of the beginning of our universe. More importantly, he addresses some of the recent speculations by scientists that attempt to circumvent both a beginning and a Beginner and shows that the best current scientific evidence continues to point to an actual beginning of our universe. The hypothesis that the universe came into existence through the actions of a transcendent intelligent Creator is still arguably the explanation that best fits the scientific data.”

—Michael G. Strauss, PhD
David Ross Boyd Professor of Physics
University of Oklahoma

 

“As an atheist detective investigating the existence of God, I hoped the evidence would reveal an eternal universe without a beginning because I knew the alternative would be hard to explain from my atheistic worldview. . . . Escaping the Beginning? examines the evidence for the universe’s beginning and the many ways scientists have tried to understand and explain the data. I wish I had his important book when I first examined the evidence. If I had, I would probably have become a believer much sooner.”

—J. Warner Wallace
Dateline-featured Cold-Case Detective
Author of God’s Crime Scene

“There are few books I read twice. but this is one of them. Although understanding this book will take effort  for anyone untrained in the sceinces, the effort is well worth it. Dr. Zweerink answered many of my questions about the existence of the multiverse, evidence for the beginning of the universe, and problems for common challenges to divine creation. . . . Escaping the Beginning? deserves wide readership by believers and skeptics alike.”

–Sean McDowell, PhD, Author of Evidence that Demands a Verdict

 

“Jeff Zweerink has done something I might have thought to be impossible. He has made cosmology accessible to scientific laypersons like me. Whether it’s quantum fluctuations, inflation theory, or the various models of the multiverse, Zweerink explains things clearly and with good humor. Even more importantly, he shows that the findings of modern cosmology give Christians even more reason to worship and adore our great God who created all things.”

-Kenneth Keathley

Senior Professor of Theology, Southern Baptist Theological Seminary.

“Does the universe have a beginning, or has the physical realm existed forever? This is an ancient question and still hotly debated today. The interest in the subject is not just from its obvious scientific significance, but also from its religious implications. Since the first cosmological and theoretical evidence for a universe with a distinct beginning was discovered a century ago, some of the most intense opposition among scientists to the notion of a beginning has been primarily on religious grounds. In this engaging book, Jeff Zweerink reviews the state of the theory and experiment, and argues that far from having been escaped, a bginning to the universe is the likely outcome of the current lines of research.”

-Bijan Nemati

Principal Research Scientist, University of Alabama in Huntsville.

“Did the universe have a beginning? If so, what would that imply? Does the origin require an Originator? Does a creation imply a Creator? What would that mean for our lives?

Paul Valery once said, “What is simple is wrong, and what is complex cannot be understood.” Dr. Zweerink splits the horns of this dilemma by raising many of the issues surrounding a cosmological beginning in an enjoyable  and accessible format for a general audience. yet this is done without sacrificing the critical details that attend the state-of-the-art.

He draws on his training and expereince as an astrophysicist to unpack the history of the big bang, its blossoming into the universe around us, and otther topics of fascination, interest, and wonder. Dr. Zweerink then goes to the heart of contemporary cosmology to find out what today’s cosmologists – our secular priests -are saying about cosmic origins.

While I might believe the scientific case for a beginning and a Creator is a bit stronger than Jeff does, his grasp of the issues and presentation style will serve his audience well.”

-James Sinclair

Senior Physicist, United States Navy.

 

“I had the privilege of debating Jeff Zweerink on two occasions. As an atheist, I was surprised to see how much common ground there was between us. And that is because Jeff is an incredibly honest and thoughtful person and his writing reflects that. Escaping the Beginning? is a well-written and carefully researched work that doesn’t shy away from challenges to cherished belief and deserves to be widely read by the community. It does what a good book should do—educate and (I hope) stimulate thoughtful debate.”

—Skydivephil
Popular YouTuber and Producer of the Before the Big Bang Series
Featuring Exclusive Interviews with Stephen Hawking, Sir Roger Penrose,
Alan Guth, and Other Leading Cosmologists

 

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.

     

     

    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.

     

    Product Review: Zeiss Terra ED 8 x 25 Pocket Binocular.

    The Zeiss Terra ED 8 x 25: a noble gesture from a market-leading optics firm.

    October 1 2019

    Preamble;

    Review A

    Review B

     Review C(verified purchaser):

    Although I read glowing reports for these pocket Zeiss Terra ED 8×25 light carry binoculars, my previous 4 month ownership of the Swaro CL 8X25 pockets had tempered my expectations. However, I found these small glassing gems to perform optically and ergonomically within 95% of the venerable and well built CL’s (at 1\3 the price)! They, just as the CL, have handling and comfort limitations compared to compact or full size binoculars. But for quick trip non-intrusive viewing, ease of portability and very accurate powered views, these little pockets are hard to beat. Overall, they possess very nice ergonomics, have natural color presentation, crystalline resolution that is real sharp and bright, with very good contrast views. Their FOV (field of view), whose sweet spot extends to within 10% of their wide 357ft limit, has a comfortable and stereoptic DOF (depth of field) . Hinge tensions are perfect, and the focuser is fast, going from close focus (mine’s about 5ft) CW to infinity in just 1.25 turns. Eye cup adjustments lock fully in (for eye glass wearers) and fully out (non-eye glass wearers). My vision is 20\15 and with the very comfortable eye cups fully extended and resting on my brow, I can align the small EP (exit pupil=3.1) with my pupils, gaining a full unobstructed sigh picture! With its ED glass, CA (chromatic aberrations) is well controlled and I find day light\low light viewing to be bright, natural and enjoyable! Diopter is set on the front dial (for the right barrel) and has enough resistance to stay put. Made in Japan for Zeiss, they offer a lot of features and performance at a great value point. These will make great travel companions and will be back-ups for my full sized field excursion instruments!

    Review D(verified purchaser):

    I also read about these on an astronomy forum, where I got the “use” info below, but not the specs.
    Buy these now. A best buy. Here’s why:
    1. Zeiss is a world class optics company. So is Swarovski.
    Compare this Zeiss Terra ED 8×25 to the world-class Swarovski 8×25 at $819 on Amazon (list price is even higher). This will show you
    a) specs are same: field of view (6.8˚),
    brightness (14.1 vs 14.2),
    weight (11 vs 12 oz),
    eye relief (16 vs 17mm), and
    size in inches
    b) specs favor Swaro: water resistant to 4 meters (vs 1 meter for Zeiss)
    c) specs favor Zeiss: close focus 6.2ft (vs 14.2 for Swaro),
    operating temperature -20 to 144˚ (vs -13 to 131 for Swaro)
    d) use favors Swaro: view is said to be more comfortable to look at, ergonomically
    focus has lighter touch, for those who like that
    e) use favors Zeiss: view is more crisp, contrasty (Swaro view is said to be softer, more milky)
    focus has firmer touch, for those who like that
    f) price favors Zeiss: $293 (vs $819 for Swaro)2. Compare them to other Zeiss binos from the SAME series – Zeiss Terra ED.
    – 8×25, 10×25 are made in Japan
    – 8×25, 10×25 are getting great reviews, for small binos
    – all larger Terra ED models are made in China
    – all larger models are getting panned for poor optics and build quality
    I think everybody is well aware that China optics and build quality are inferior (so far) to those from the US, Japan, Taiwan, Germany, Austria, etc.So this 8×25 model is unusual. Superior optics and build are normal for Zeiss, except for their Chinese built Terra ED line.
    Luckily, the 8×25 model is made in Japan with Zeiss design. This results in typical world class Zeiss quality.What is hard to understand is how Zeiss makes a $293 optic that arguably outperforms an $819 Swarovski.For bino newbies looking at 10×25, remember: the 10×25 will have a smaller exit pupil, so your views may black out more. Also, a 10x is way harder to hold steady and actually see than an 8x. So, even though you think you want 10x, you probably really want 8×25. With the 8×25, you’ll actually see and enjoy the view more.………………………………………………………………………………………………………………………………..

    What you get:

    The Zeiss Terra ED 8 x 25 pocket binocular kit.

    The Zeiss Terra pocket arrived double-boxed. After opening the outer packaging, the binocular kit was housed inside a very nicely presented box with a very fetching design which folds open to reveal the contents. Unlike other products I’ve received in the past, the Zeiss box has depicted on the inside, a colourful alpine scene with majestic mountain peaks soaring high above a beautiful river valley. Perhaps the team at Zeiss intended the user to explore such landscapes? Whatever the reasoning behind it, it was certainly a pleasant touch.

    With Zeiss, even the packaging is premium.

    Unlike customers who bought the Zeiss pocket binocular when it was first launched just a few years ago, I was relieved to see that the instrument was housed inside a small clamshell case with a magnetic latch carrying the blue & white Zeiss logo.The box also contained a lanyard, operating instructions and a lens cleaning cloth. I was surprised that the binocular itself came neither with eyepiece or objective lens caps, but I suppose they are not really necessary, as the case very effectively protects the instrument from dust and moisture.

    The box has the serial number on the side, which is needed to register the product on the Zeiss sports optics website.  On another side of the box, the detailed specifications of both the 8 x 25 and 10 x 25 models are presented; another nice touch.

    The binocular was housed inside the clamshell and was pristine, with no dust on the lenses, or gunk on the interior of the barrels. From the moment I prized the neatly folded instrument from its case, I was impressed. The frame is composed of a fibre-glass like polymer, with a fetching black, grey and blue livery. The sides of the binocular have a rubberised exterior making it easy to grip well while in use. The double-hinges were rigid and hold their positions solidly once the correct inter-pupillary distance is chosen for your eyes. The optics are hermetically sealed, nitrogen purged and had immaculately finished anti-reflection coatings on both the ocular and objective lenses. They are also treated with a Zeiss’ proprietary hydrophobic coating that encourages any moisture and grime that gathers on the lenses to fall off, rather than accumulating on the surfaces. The instrument is guaranteed to operate flawlessly over a very impressive temperature range: -20C to +63C, so covering almost any environment it is likely to find itself in.

    The binocular is water resistant, but to what degree remained a bit of a mystery owing to the rather odd way in which Zeiss chose to present it: 100mbar.

    You what mate?

    Thankfully, some physics knowledge helps to clarify the reference to water pressure.

    P = Rho x g x h, where P is the water pressure, Rho is the density of water, g is the acceleration due to gravity and h is the depth in metres. Rearranging to find h gives;

    h = P/ (g x Rho) = 10^4/ (10 x 10^3) = 1m

    Knowledge is power lol!

    So, not as waterproof as a Swarovski pocket binocular(I think it’s 4m) but adequate for most purposes.

    Fully folded down, the Zeiss Terra pocket is about 70mm wide and 110mm long. The oversized barrels make the Zeiss a wee bit taller when placed on its side in comparison to a classic pocket instrument, like my lovely little Opticron Aspheric LE;

    The Zeiss Terra Pocket(right) is a little wider and taller than the more conventional Opticron Aspheric(left).

    The Terra weighs in at 310g, so about 40 grams lighter than the Swarovski-made counterpart. Lighter isn’t necessarily better however, as some individuals find holding such light glasses problematical. But once unfolded, the significantly wider barrels more than make up for its low mass, as I shall explain more fully a little later in the review.

    The eyecups look a bit suspect, but once you begin rotating them, they work really well. They have no indents but do have ample friction. There are only two positions; fully retracted or fully extended. You know you’ve reached either situation by hearing their clicking into place. They are very solid and hold their positions superbly. Eye relief is 16mm and I was able to enjoy the full field with eye glasses on or without. Placing your eye on the eyecups is very comfortable, with their soft, rubberised overcoat and the large field lenses makes for very easy centring of your eye sockets along the line of sight of the optical train.

    The dioptre(+/- 3) setting lies at the other end of the bridge(near the objectives), which initially presented some problems for me, as it is rather stiff and difficult to get going, but once you’re done you’re done! The focusing wheel is centrally located and is reassuringly large and easy to grip, even with gloves on. It moves very well, with the perfect amount of tension. Motions run smoothly, with little in the way of play or backlash when rotated either clockwise or anti-clockwise. The focuser requires one and a half full rotations to go from one end of its focus travel to another.

    The Zeiss Terra ED 8 x 25 has a large, centrally placed focuser. The right-eye dioptre ring is located at the other end of the instrument, near the objective lenses.

    The objective lenses are very deeply recessed, more so than on many other pocket binoculars I’ve used. This affords the 25mm objective lenses greater protection against aeolian-borne dust and also serves as a first-line defence against glare. Cool!

    As the other reviewers showcased earlier, the Zeiss Terra pocket binoculars are manufactured in Japan, with the larger models originating in China under Zeiss supervision. You can see that quite clearly by examining the under belly of the instrument:

    The underside of the binocular reveals its country of manufacture: Japan.

    That said, and contrary to what the other reviewers have asserted, I don’t fully subscribe to the notion that all Chinese-made binoculars are inferior to those produced in Europe or Japan, as I shall elaborate on later.

    All in all, it’s pretty obvious that a great deal of sound engineering was put into these pint-sized field glasses.

    Handling: The Zeiss pocket is supremely comfortable to use, the slightly larger frame fitting comfortably in my hands. Indeed, with its wide field of view and thicker barrels, it feels like you’re peering through a larger instrument. The big eye lenses make it easy to get the right eye placement with none of the blackouts I’ve experienced on a number of other pocket binoculars. Its light weight means that you can carry it round your neck for hours on end with no neck strain. Its easy to get both hands resting on the central bridge, using my little finger to engage with the focus wheel.

    Optical Assessment:

    Straight out of its case, the Zeiss Terra impressed. Looking at some tree trunks just beyond my back garden fence reaveled a wealth of high contrast detail. I was immediately taken aback with the expansive field of view; not only was it wide, but the image remained tack sharp across nearly all of the field. Images snapped to a very sharp focus and I experienced no trouble focusing from just a few yards away all the way out to some trees located hundreds of yards away. Glare suppression looked excellent, even when pointed at some backlit scenes strongly bathed in sunlight. It was immediately clear to me that I was looking through a very high quality optical instrument.

    As I stated in earlier blogs, I don’t really consider the inclusion of low dispersion (ED) glass as necessary in a small binocular like this, but it’s a nice feature when presented as part of a larger, properly designed system. After all, and as several other reviewers pointed out, the Zeiss seemed quite comparable to arguably the most sought-after pocket binocular on the market; the venerable Swarovski CL pocket binocular. But what is not widely communicated is that the latter achieves all its optical excellence without using ED glass. That should send a powerful message to the gayponaut propagandists. No, its all about using great glass, great coatings and solid mechanical engineering. Alas, I was not able to compare this pocket binocular with the Swarovski, but the fact that the little Zeiss was often mentioned in the same company as it speaks volumes about its optical quality.

    Further daylight tests showed that off-axis aberrations were very well controlled. Even at the edge of the field pin cushion distortion and field curvature were minimal. Looking straight up at a denuded tree branch against an overcast sky showed no colour fringing on axis but as the image was moved off axis, some slight secondary spectrum was noted. Overall, I was very impressed at the Zeiss’ optical quality; it really does exactly what it says on the tin!

    A niggly moment: While the little Zeiss pocket binocular fits perfectly inside its small, clamshell case without the supplied neck strap attached, I found that the addition of the strap made it very difficult to get a snug fit. Wrapping the neck strap around the central bridge simply didn’t allow the case to close properly(the magnetic latch never stuck), but after several attempts experimenting with different approaches, I finally hit on a way to get the binocular with its strap on to fit the case. The trick involves wrapping the strap tightly around the ocular lenses.The latch sticks.  Problem solved!

    More discriminating optical tests:

    Flare & Glare assessment:

    Even if the glass used in binoculars were mined from the asteroid belt, it counts for nothing if it can’t control light leaks. My initial daylight tests showed that glare and internal reflections were very well controlled in the little Zeiss binocular, but they can’t tell the whole story. So, I set up my iphone torch at its brightest setting in my living room and examined the focused images through  the Zeiss Terra, comparing its results with my Opticron Aspheric(a nice little performer) as well as my control binocular; the Barr & Stroud 8 x 42 Savannah, which has excellent control of stray light.

    The results were very interesting. The Zeiss faired better than the Opticron, but not by much. However, it was not as good as the Savannah, which exhibits exceptional control of internal reflections even though it collects far more light than any pocket binocular.

    Further testing of the binoculars on a bright street light revealed some additional information. Internal reflections were well suppressed in both the Zeiss and Opticron binoculars, but the Zeiss showed more prominent diffraction spikes. The Savannah control binocular, in comparison, proved superior to both pocket binoculars. It shows very little flaring and internal reflections and much better control of diffraction spikes.

    And therein lies an instructive lesson. The Barr & Stroud Savannah 8 x 42 is fabricated in China yet shows exceptional control of glare and internal reflections. So, it’s not so much where a binocular is built that counts so much as how it is constructed.

    An exceptional, Chinese-made binocular; the Barr & Stroud 8 x 42 Savannah wide angle 143m@1000m.

    It is all the more remarkable, since the Savannah can be purchased for half the price of the diminutive Zeiss!

    All in all, these tests showed that the Zeiss binocular is very well protected against stray light, glare and internal reflections and this goes a long way to explaining why the views through it are so compelling.

    Collimation and Field of View Tests:

    I checked the collimation of the barrels on the Zeiss by placing the instrument on a tall fence and aiming at a rooftop, checking that both the horizontal and vertical fields correlated with each other. They matched up very well.

    Field of view is best assessed by turning the binocular on the stars. Accordingly, I aimed the Zeiss Terra at the two stars at the end of the handle of the Ploughshare, now low in the northern sky. The Zeiss was able to image both Mizar and Alkaid in the same field with a little bit to spare. These stars are separated by an angular distance of 6 degrees 40′ (or 6.66 degrees). This result was consistent with the specifications on the inside of the box; 6.8 angular degrees.

    Further Observations:

    Comparing the Opticron Aspheric to the Zeiss Terra in daylight, showed that both instruments were about equally matched in terms of sharpness( the aspherical oculars on the Opticron certainly help in this regard), but I could discern that the image was that little bit brighter in the Zeiss. Better coatings in the Zeiss binocular throughout the optical train give it the edge in this regard. Field of view was also much more expansive in the Zeiss( the Opticron has a true field of 5.2 degrees in comparison). Colours were also that little bit more vivid in the Zeiss pocket binocular, caused perhaps by its better contrast and superior control of chromatic aberration.

    Close focus is very good. I measured the Zeiss Terra to have a minimum close focus distance of 1.4 metres, so this should be a great little instrument for use as a long distance microscope, to spy out insects, fungi, flowers, rocks and the endlessly fascinating complexities of tree trunks.

    The eye lenses on the Zeiss Terra pocket binocular measure 18mm in diameter, the same as the Swarovski CL pocket. But they are still small in comparison to a larger format binocular like my 8 x 42.

    But while the field of view is quite immersive in the Zeiss Terra, it lacks the majesty factor of a larger binocular, such as my Barr & Stroud 8 x 42 Savannah, with its whopping 8.2 degree true field and better eye relief. Larger binoculars are simply easier to engage with your eye sockets and are thus more comfortable to use than any pocket binocular on the market.

    Performance under low light conditions easily show the limitations of the small objectives on the Zeiss Terra. At dusk, the 8 x 42 was vastly superior to the Zeiss, showing much brighter images, as expected. So, as good as the Zeiss pocket binocular is, it can’t defy the laws of physics.

    A Walk by the River Bank

    River Endrick, near my home.

    One of the best reasons to own and use a pocket binocular, is that it encourages you to go outside and explore the landscape. They’re so light weight and handy that anyone can carry one. Sometimes I use the Opticron and at other times I like using the Zeiss. Their sharp, high-contrast optics deliver wonderful images of the Creation. For me, nature is life affirming; a profound source of revelation and illumination. Like a great Cathedral, it fills me with awe and wonder. The sound of the wind whistling through the trees, the babbling brook and the noisy chirps of small tree birds form part of a symphony paying homage to the One who fashioned it all. For some, the Darwinian, materialist lie has dulled or even extinguished the sense of wonder that is innately endowed to every child. Dead to the world, believing themselves to be highly evolved animals, they pose no meaningful questions and can give no meaningful answers to life’s biggest conundrums. As you think, so you are.

    But it doesn’t have to be that way!

    For me, being able to explore the wet and wild places with tiny optical aids is a source of unending joy. On sunny afternoons or early in the morning, I sometimes take myself off for a walk along the banks of the River Endrick which meanders its way through the beautiful valley in which I live. Streches of shallow, fast-flowing water predominate but are also complemented by deeper pool and riffle sequences; favourite haunts of  Brown Trout, Perch and other course fish. Lanky Herons frequent these waters in search of fresh prey.  Bracken flourishes all along the river, and my pocket binocular allows me to study their shape and form in great detail. As summer gives way to autumn, their bright lorne hues transform into various shades of brown and tan. Spiders weave elaborate but deadly webs of silk with their spinnerets that sparkle and glisten in the morning sunlight, creating a wondrous decoration that I can experience up-close and personal with my long range microscope.

    Towering trees soar into a blue sky by the banks of the Endrick.

    Many species of tree grace the banks of the river; Ash, Silver Birch, Sycamore, Horse Chestnut and even the odd Oak. Thriving from frequent rain showers, their trunks are covered in lichens, moss and algae that reveal a wealth of intricate structure and a riot of colour that changes in accordance with the varying altitude of the Sun as it wheels across the sky. I especially delight in observing the colour of autumn leaves in bright sunlight, the ruby reds of anthocyanins and the yellow-orange hues of carotenoids. Every now and then, I watch as the fast-flowing water, dappling in weak autumn sunshine, ferries off fallen leaves, their destinies unknown. My pocket binocular shows me that every tree trunk is unique. Each tells its own story, visual scars of its past life.

    On some stretches of the river bank, I can still find some late-flowering wild plants that delight the eyes with colour in unexpected ways. And as autumn continues its march towards winter, the thick brambles begin to yield their succulent fruit. What could me more pleasing and more natural than to feast on their nutritious berries?

    An expected riot of autumn flowers observed along the river bank.

    At some places along the river bank, there are expansive rocky stretches. And yet every stone you unturn reveals even more of God’s Creation. A scurrying earwig, a wondrously armoured wood louse or a frollicking spider.The pocket binocular brings everything into stunning clarity. And though at first glance, each stone looks more or less the same, my little pocket spyglass shows that they too are all unique. Every crevice, every colourful grain is one of a kind.

    A rocky stretch along the river bank.

    This tiny corner of the world is ripe for exploration, with every day that passes presenting new adventures, new wonders to delight the eye. But so is yours!

    Bird Watching with the Zeiss Terra Pocket Binocular:

    Can good pocket binoculars be suitable for birdwatching?

    Lots of birding websites don’t recommend using pocket binoculars for birdwatching, citing their small fields of view and reduced comfort compared with larger binoculars as the most common reasons. Having used these small binoculars for a while now, I must say  that I respectfully disagree. The Opticron Aspheric has served as a good birding binocular for me, especially for quick looks at birds that visit our back garden table and the crows that nest in the conifer trees in the common ground beyond our back yard fence. Recently, a group of five magpies have taken up residence in the Rowan tree in our back yard. Each evening as darkness falls, they hunker down in the tree and don’t seem to be fazed by us turning on an outside light or noisy disturbances when it’s time to put the garbage out. During the day though, they are often seen chackering away at each other loudly(magpies don’t actually sing) as if to resolve some dispute among themselves. Further afield, there is a small pond just a few hundred yards away in the grounds of Culcreuch Castle, which attract quite a few varieties of water bird; swans, duck, water hens, heron and even the odd cormorant. Once I learned to use them properly, small binoculars like these have never presented much in the way of a problem for me.  And since the Zeiss Terra pockets have a nice wide field of 6.8 degrees, they have proven to be better suited than the Opticron in this regard because you can better track the motions of birds with a wider true field.

    On the Zeiss Sports Optics website, under ‘usage’, they seem to be saying that the Terra pockets are less suitable for birding, but I wonder if this is merely a clever ploy to get folk to buy into their larger(and more expensive) models. If so, they’re lost on me. With their excellent optics and generous field of view right to the edge, they can and do serve as good birding glasses. Of course, you can only form your own opinions by actual field experience but you may discover that the little Terra is all you really need! Seen in this light, acquiring a Zeiss Terra pocket binocular can actually serve as a cost-saving measure that stops you haemorrhaging your hard-earned cash on ever bigger and more expensive models.

    How About Astronomy?

    A small binocular like this is not the best for exploring the night sky since its small objective lenses cannot gather enough light to really wow the observer. However, the Terra’s excellent performance both at the centre of the field and extending nearly all the way to the edges, as well as its wonderful contrast make star gazing a pleasant experience. Out here in the sticks, the sky is quite dark and rewarding, even when observed with such a small instrument. Its field of view is large enough to enjoy some of the showpieces of the sky like the Pleiades, the Hyades, and larger asterisms such as Melotte 20 in Perseus, which can be taken in with its generous field of view. Stars remain very tightly focused and pin sharp across the field. Later in the season, I look forward to exploring the winter constellation of Orion the Hunter, to seek out its magnificent nebula in his Sword Handle, as well as the many delightful clusters of stars that are framed within its borders.

    On another autumnal evening, I was able to pick up the three Messier open clusters in Auriga, M34, the Messier galaxies, M81 and M82, the Andromeda Galaxy, the Double Cluster in Perseus, wide double stars like Mizar & Alcor and the Coathanger asterism in Vulpecula. Running the binocular through Cygnus and Cassiopeia will also reward dark-adapted eyes with innumerable faint stars, like fairy dust on black velvet. One delightful little project involves exploring the lovely colours of bright stars such as blue-white Vega and Sirius, creamy white Capella, brilliant white Rigel, orange Arcturus and fiery red Betelgeuse and Aldebaran.

    Following the phases of the Moon can also be a rewarding and worthwhile pursuit, as the Terra’s above average glare and internal reflection control will ensure that you get nice crisp, contrasty images. Lunar eclipses can also be enjoyed. You might also like to try your hand at observing the beautiful light shows presented by clouds passing near the Moon on blustery evenings. The excellent contrast of the Terra will also allow you to see stars around the Moon which can be very arresting to observe. Capturing the bright Moon as it rises over man-made buildings will also delight the eye. Above all else, don’t let its small aperture deter you from exploring God’s wonderful creation, which fills the Universe with hope and light.

    Final thoughts:

    Terra: for exploring the Earth and beyond.

    The Zeiss Terra ED 8 x 25 pocket binocular is a fine, high-quality optical instrument that is easy to use and transport. If taken care of, it will give you years of enjoyment where ever you wish to take it. As I said from the outset of this blog, I believe Zeiss did something very noble in bringing this little binocular to market at the price point they set. To be honest, and as others have quipped, they could well have stuck a ‘Victory’ label on it and no one would be any the wiser. Optically, Zeiss engineers have cut no corners to deliver an ergonomic, durable and optically sound instrument that will delight anyone who looks through it. I suspect that the Zeiss Terra pocket might be one of their best-selling products. It is even available on finance and buy-now-pay later schemes here in the UK, although I would strongly advise would-be buyers to save up and pay the price in full rather than incurring more debt, where you ultimately pay more. The Zeiss is expensive as small binoculars go, but I feel that it’s worth every penny, as for me at least, it has already given me countless hours of wonderful experiences. In the world of high-quality pocket binoculars, the Terra certainly stands out in a crowd. Highly recommended!

     

    Thanks for reading.

     

    Neil English is the author of a large medley of essays(650pages), Chronicling the Golden Age of Astronomy, which showcases the extraordinary lives of amateur and professional astronomers over four centuries of time.

    Post Scriptum:

    1. The Zeiss Terra has a two year warranty, which is enacted once you register the product on the Zeiss website. Cross-checking is thorough, requiring the serial number, and the name & address of the place of purchase. After checking these details, you receive a confirmatory email from the Zeiss Sports Optics team, welcoming you to the world of Zeiss.

    2. The little foldable Zeiss Terra is very suitable for those adults with unusually small inter pupillary distances (closely spaced eyes) and children.

    3. The overall light transmission of the Zeiss Terra ED is 88 per cent. Source here. This is exactly the same as the Swarovski CL Pocket(non-ED just in case Pepperidge farm forgets, ken ) binocular. Source here. Zeiss Victory Pocket binocular light transmission is 91%. Source here.

    4. The family of magpies came back to the Rowan tree in my garden, as they always do, just before sunset. Here is a picture of four ( I think!) individuals settled in the tree branches at 20.09pm local time on the evening of October 6 2019.

    Wee magpies hunkering down for the night in my Rowan tree.

    5. After a week of abysmal weather, with endless cloud and rain, I finally managed to test the little Zeiss Terra pocket binocular on a very bright gibbous Moon at 10:25pm local time on the evening of October 10 2019, when it was within an hour of meridian passage. At the centre of the field, it delivered a beautiful, clean and razor sharp image with no false colour. The background sky was good and dark with little in the way of diffused light. Internal reflections were pretty much non-existent with the Moon in the centre of the field. Only when it was placed just outside the field did I detect some minor flaring. Moving the Moon to the edge of the field threw up some slight lateral colour, bluish at its southern edge, and green-yellow at its northern edge. These results were entirely consistent with my flashlight testing. This will be a useful Moon-gazing glass!

    De Fideli.

    Product Review: The Opticron Aspheric LE WP 8 x 25 Pocket Binocular.

    A fine compact binocular at a fair price.

    Tiny little pocket binoculars have grown on me.They can be supremely useful to those who value or need ultra-portability, when larger binoculars simply are unworkable. Their tiny size ensures that they can be carried in a pocket or a small pouch, where they can accompnay hikers, hunters, sports enthusiasts, bird watchers and nature lovers who delight in seeing the full glory of God’s created order. Frustrated by a lack of any credible reviews of a variety of models, I began a ‘search out and test ‘ program that would teach me to select models that offered good optical and mechanical performance, as well as good value for money.  As you may appreciate, this was far easier said than done, but in the end, I did find a model that I could trust to deliver the readies; enter the Opticron Aspheric LE WP 8x 25 binocular.

    Retailing for between £120 and £130 ( ~$175 US), the little Opticron pocket binocular didn’t come cheap. But good optics and mechanics are worth having, especially if the user intends to employ the instrument on a regular basis. As I explained, I chose this model based on the performance of a first generation Opticron Aspheric that I had purchased some time ago for my wife, possessing identical optical specifications to this newer model, but without having the additional advantage of being nitrogen purged, as well as being water and fog proof. In truth, I chose the original model without much in the way of research and with very little experience of what the market offered; Opticron is a good make, trusted by many enthusiasts for delivering good optical performance at a fair price.

    Opticron began trading back in 1970, founded as a small British family firm, and offering binoculars, spotting scopes and other related sports optics for the nature enthusiast. Since those founding days, Opticron has continued to innovate, where it now is a major player in this competitive market, offering well made products catering for the budgets of both novices and discerning veterans alike. And while some of their less expensive models are made in China, many of their high-end products are still assembled in Japan.

    What you get.

    What your cash buys you: The Opticron was purchased from Tring Astronomy Centre. It arrived double-boxed and with no evidence of damage in transit. You get the binocular with both ocular and objective covers, a high quality neoprene padded case, a comprehensive instruction manual & warranty card. The details of that all-important warranty are shown below:

    Details of the warranty.

    After a few days of intensive testing I was satisfied that I had received a high quality instrument and so I elected to register my binocular on the Opticron website.Owners are not obligated to register the instrument in this way however, as all that is required is proof of purchase, should any issue arise with the instrument in normal use.

    Binocular Mechanics: The Optricron Aspheric LE WP 8 x 25 is a classically designed pocket binocular with a double-hinge designed allowing the instrument to fold up into a very small size that can be held in the palm of your hand. The hinges have just the right amount of tension, opening up and holding their position even if held with one hand.

    The focuser is slightly larger than the first-generation model, and has better grip, allowing you to use it even while wearing gloves. The barrels and bridge of the binocular are made from aluminium, overlaid with a tough, protective rubberised armouring. Compared to the first-generation model,  the new incarnation induces more friction with your fingers, an important feature if it is to be used for extended periods of time.

    The New Opticron Aspheric LE is now water and fog proof.

    Initially, I found that turning the focuser to be a bit on the stiff side, but after a few days of frequent use, I became used to it. Turning the focuser either clockwise or anticlockwise showed that there was no backlash, moving smoothly in either direction. The instrument has an integrated neoprene lanyard which can be wound up around the bridge while being stored in its case. I very much like this rather understated feature, as there is no need to fiddle about attaching a strap. Out of the box, it’s ready to use!

    Using the Optricon Aspheric LE WP is child’s play; just twist up the eyecups and they click into place. There are no intermediate settings. If you wear glasses, leave the eyecups down.

    The twist-up eyecups have a soft rubberised overcoat which are supremely comfortable on the eyes. There are just two positions; fully down or fully up. Once twisted up, the cups lock in place and rigidly stay in place with a click. Eye relief is very generous(16mm), allowing eye glass wearers to engage with the entire field. I don’t use glasses while observing through binoculars, so I always pop the eyecups up while viewing through them. Optimal eye placement is very easy to find quickly, thanks to the large field lens, with none of the annoying blackouts I experienced on a few lesser models.

    The dioptre setting is located in a sensible place; right under the right eyecup. A small and very elegantly designed protruding lever on the dioptre ring makes it very easy to rotate either clockwise or anti-clockwise. It works well and stays in place even after repeatedly removing the instrument in and out of its small carry case.

    An elegant design feature; a small protruding lever under the right eyecup makes it easy to adjust the dioptre setting.

    I measured the interpupillary(IPD) range to be between 32 and 75mm, ample enough to accommodate most any individual. Moreover, the well designed dual hinges on the bridge ensure that once deployed they stay in place with little or no need to micro-adjust while in use. The Opticron pocket binocular weighs in at just over 290 grams.

    If the Opticron Aspheric pocket binocular were a car, it would surely be an Aston Martin.

    Optical Assessment: Although this tiny binocular does not have a stalk to allow it to be mated to a monopod or tripod, I was able to assess how well collimated it was by resting the binocular on a high fence, and examining the images of a rooftop some 100 yards in the distance, checking to see that the images in the individual barrels were correlated both horizontally and vertically. This was sufficient to affirm that the binocular was indeed well collimated.

    During daylight hours, the binocular delivers very bright and colour-pure images thanks to a well made optical system which includes properly applied multi-coatings on all optical surfaces, good baffling aginst stray light and silver coated prisms(boosting light transmission to 95-98 per cent). The binocular also has correctly executed phase coatings on the prisms to assure that as much light as possible reaches the eye. Sharpness is excellent across the vast majority of the field, with the aspherical optics minimising off-axis aberrations including pincushion distortion and field curvature. I wouldn’t be surprised if the overall light transmission is of the order of 80 to 85 per cent(revised in light of the tranmissitivity of the Zeiss Terra ED pocket glass with a light tranmsission of 88 per cent).

    One of my pet peeves is seeing glare in the image when the binocular is pointed at a strongly backlit scene. I was delighted to see that apart from very slight crescent glare  when pointed near the Sun, the images generally remained stark and beautifully contrasted. These good impressions were also confirmed by more stringent tests conducted indoors by aiming the pocket binocular at my iphone torch set to its maximum  brightness. These tests showed that although there was some weak internal reflections  and flare, they were well within what I would consider acceptable. At night, I was able to see that when the binocular was aimed at some bright sodium street lamps, only very slight ghosting was evident. Finally, aiming the 8 x 25 at a bright full Moon revealed lovely clean images devoid of any on axis flaring and internal reflections. Placing the Moon just outside the field did show up some flaring however, but I deeemed the result perfectly acceptable. You can chalk it down that these results are excellent, especially considering the modest pricing of the instrument.

    Colour correction was very well controlled in both daylight and nightime tests on a bright Moon. On axis, it is very difficult to see any chromatic aberration but does become easier to see as the target is moved off axis. That said, secondary spectrum was minimal even in my most demanding tests, affirming my belief that a well-made achromatic binocular can deliver crisp, pristine images rich in contrast and resolution.

    ……………………………………………………………………………………………………………………………….

    An interesting aside: My former colleague at Astronomy Now, Ade Ashford, reviewed a larger Opticron binocular- the Oregon 20 x 80 – for the October 2019 issue of the magazine. In that review, featured on pages 90 through 94, he confirmed what I had previously stated about larger binoculars with powers up to 20x or so; there is no need to use ED glass if the binocular is properly made and this goes for both daylight viewing and nightime observations. Below is Ashford’s assessment of the 20 x 80’s daylight performance:

    And here are his conclusions:

    Moreover, Ashford offers this sterling advice to the binocular enthusiast:

    ” …..don’t get hung-up on ED glass instruments. A well-engineered achromatic model will perform well, particularly if it uses Bak-4 prisms and its optical surfaces are multi-coated throughout.”

    pp 91

    Having ED glass counts for nothing if the binocular is not properly made. I would much rather have a well made achromatic instrument than have a poorly constructed model with super duper objective lens elements.

    …………………………………………………………………………………………………………………………..

    A fine quality pocket binocular in the plam of your hand.

    My Little Aston Martin:

    The little Opticron has already accompanied me on a few hill walks, a Partick Thistle FC( sad, I know!) testimonial and numerous rambles near my rural home, where it has delivered wonderful crisp images that never fail to delight. The field of view(5.2 degrees) is a little on the narrow side as pocket binoculars go, but its plenty wide enough for most applications and besides, the distortion free images nearly from edge to edge quickly override any perceived handicap of having a restricted viewing field.

    Its tiny size and lack of garish colouring make it the ideal instrument to bring along to sports events, where it doesn’t attract attention from fellow crowd members. The Opticron is also a most excellent instrument to examine colourful flowers, butterflies and other marvels of nature near at hand, thanks to its excellent close focus; measured to be ~51 inches.And because its waterproof, it would also make an excellent companion while sailing or fishing.

    The Opticron pocket binocular comes with a very high quality padded pouch to protect the instrument from any kind of rough handling.

    Of course, the power of a small, high-quality pocket binocular quickly dwindles as the light begins to fade in the evening, or during the attenuated light before dawn, where a larger field glass really comes into its own. A little pocket binocular like this is far from the ideal instrument for viewing the night sky, but it can still be used for the odd look at the Moon, a starry skyscape or brightly lit cityscape.

    I consider weatherproofing to be a sensible and worthwhile addition to any binocular and is certainly welcome on this second generation Opticron Aspheric. The instrument is purged with dry nitrogen gas at a pressure slightly higher than atmospheric pressure. This positive pressure helps to keep out dust and marauding fungi, and the sensibly inert nature of nitrogen ensures that internal components(including the silver coated prisms), will not tarnish or oxidise any time soon. This will only serve to increase the longevity and versatility of the binocular in adverse weather conditions, especially in my rather damp, humid climate. When not in use, I have taken to storing all my binoculars in a cool ( ~60 F) pantry with silica gel dessicant inside their cases. Yep, all my instruments are in it for the long haul.

    Quality you can wear.

    The Opticron Aspheric LE WP 8 x 25 is an excellent example of how a well made, achromatic binocular can deliver wonderful, sharp and high-contrast images. It is more expensive than many other pocket binoculars, but you most certainly get what you pay for.

     Thanks for reading!

    Neil English’s new title, The ShortTube 80; A User’s Guide, will hit the bookshelves in early November 2019.

     

    De Fideli.