Earth & Sky.

“Moonrise” by Stanislaw Maslowski (1884); image crdit Wiki Commons.

In a fallen world, where mankind’s rebellion against his Creator is now rapidly reaching pre-flood levels of wickedness, it is good to know that the planet Earth is still a pretty neat place to live. Protected by a just-right atmosphere of mainly nitrogen and oxygen, the Lord of Heaven’s armies has packed this planet full of living things and amazing geological features that bring joy to the human heart.

Our atmosphere is neither too dense or too rarefied, allowing us to peer deeply into the Cosmos, where we have caught a glimpse of eternity.  And all around us, our Creator has left clear evidence of His handiwork so that we are without excuse on the day of judgement.

The human eye can only see so much though, but our Creator chose to give us a mind that enables us to improve our lot, to see things in new and different ways. That’s how I see my binoculars; simple tools that bring heaven and Earth closer, providing a perspective that transcends the limitations of my corporeal form. I am especially fortunate to live in a beautiful part of the world, away from the cities where atheism flourishes. Out in the sticks, I can enjoy the beauty of God’s creation more fully, in quietness, surrounded as I am by hills and valleys, green fields and lovely streams of cool, fresh rainwater that sustain the lives of all living things.

The author’s wide angle 8 x 42 binocular: extraordinary performance at an ordinary price.

My wide-angle 8 x 42 binocular, in particular, is the perfect tool for combining the beauty of the night sky with that of the comeliness of the earthly creation. And in this blog, I would like to share with you some of the kinds of activities I get up to to bring these worlds together. This binocular provides a power of just 8 diameters but has an angular field of view wide enough to fit over 16 full Moons in the same wonderful portal. And with its decent light grasp, especially in fading or low light, it is powerful enough to allow me to simultaneously appreciate sights in the heavens and on earth.

                                                  Picture Postcards

Surrounded by mature trees, sometimes many times older than myself, I have grown terribly fond of framing famliar celestial sights, such as the Pleiades and the Hyades in the foreground of their impressive branches. Sometimes, I would wait for the stars in these clusters to fall in altitude after they culminate in the south, so that they are seen to ‘hover’ over the conifer trees beyond my back garden. And if, by chance, the presence of a gentle breeze in the binocular image is witnessed (and it can happen a lot!), then you’ve got a home run; an epiphany of sorts! At other times, I will plan a vigil where the soft light from the stars fills the background whilst the foreground is occupied with denuded winter branches of the deciduous trees near my home. A little light pollution can actually be advantageous in such circumstances as it can help illuminate the tree branches making them stand out more boldly against the stellar backdrop.

Living inside a long valley with verdant hills that soar to about 1000 feet on either side, my binocular is good at framing the rising Moon as its silvery light clears their summit in the east, or as it sinks behind the hills in the west. There are many times where I can plan to observe the Moon and the hilltops in the same field, creating visual scenes that leave a deep impression on me. I give thanks to my God for allowing me to witness such scenes, safe and secure at the bottom of a great sea of fresh, clean air.

Ever since childhood, I have been attracted to storms, often venturing out to feel the energy they generate in the atmosphere. Sometimes these storms occur on moonlit nights and I would think it nothing to grab my binocular and carry myself off to some favourite haunts, woody glades and the like, where moonbeams create wonderful atmospheric scenes, complemented by the sound of wind whistling through their branches.

My binocular has renewed my interest in observing the full Moon, not in and of itself, but when it is surrounded by low lying and fast-moving rain clouds, as often happens here in the British Isles. I watch as these clouds enter the outer field, inching their way toward the bright satellite, and all the while lighting up with beautiful colours caused by refraction of moonlight through raindrops. The colours often start off deep and moody, like dried-in blood, when far from the Moon, but as they move ever closer, the colours they generate; gorgeous shades of pink, yellows and even rose tints; saturate the cones on my retina and,  upwelling feelings of great happiness.

The structure of clouds backlit by moonlight reveals wonderful, highly complex structures, as well as colours – knots, filaments and pleated sheets. Often the scene reminds me of the play of light on the matter which is expelled into the shells of planetary nebulae as imaged by a great telescope, with a white dwarf star being replaced by our very own Moon at its epicentre lol. Such natural shows of light and form rank as some of the most lovely and most surreal binocular images one is likely to capture. Sometimes, great gaping holes in the heavens open up around the clouds, allowing the light of the distant stars to be seen near the full Moon.

Dawn and dusk are good times to see some spectacular sights, such as the bright planet Venus sinking low into the sky, often silhouetted by interesting terrestrial structures, such as a distant hill,  an old barnhouse or silo, church or windmill. By getting to know your horizons, sublime scenes can be captured with your binocular, bringing heaven and Earth together, just like it will be in the New Creation.

Cityscapes can also be used to enhance the binocular view. Framing bright star clusters like the Pleiades or a crescent Moon in the background to an old church spire, domed cathedral, or grand municipal building, can make for a very fetching sight. Photographers  imagine likewise,of course, but the impromptu binocular experience is an even greater liberal art!

Another worthwhile project is to image the bright Moon over a large expanse of water, especially during calm conditions, when its  reflection  is quite mirror-like. Under the light of a town or city, smaller binoculars do just fine, like my little Pentax DCF 9 x 28 pocket instrument. You can even wander through your neighbourhood finding interesting foreground subjects to frame your celestial scenes in advance of an event.

It’s good to plan.

Well, I hope you get some ideas from this short article. In doing so, you can enjoy the best of the heavenly and terrestrial creations, and which can turn an otherwise mundane evening or morning into a very memorable one!

Happy hunting!

 

 

Neil English is the author of several books in amateur and professional astronomy.

 

 

 

De Fideli.

Product Review: The Pentax PCF WP II 20 x 60 Binocular.

Grandes Binoculares.

The achromatic telescope has enjoyed a long and illustrious career in the hands of skilled observers. In my most recent book, Chronicling the Golden Age of Astronomy, I have documented and shared with you the amazing achievements of the classical refractor over three centuries of time. But it would be quite inaccurate to claim that it has been really superceded by anything else in the modern age. This is especially true in the case of binocular manufacture, where sales of achromatic instruments vastly outsell models which possess modern ED glass. And there’s a good reason for this: ED is an expedient luxury that impacts little to the binocular view, what with their low magnifications and wide fields. For every ED model offered, there are a great deal more made with traditional crown & flint, and that is true even for some premium brands.

Consumers vote with their wallets.

We still live in the achromatic age.

Having enjoyed and appreciated the achromatic refractor for decades, I have come to the conclusion that it is in the binocular that achromatic optics has reached its zenith. Properly made, achromatic optics provide wonderful, sharp and contrasty images of the eartly and heavenly creation. This conclusion has been reached by extensive field experience of a variety of achromatic binoculars that show vanishingly small amounts of secondary spectrum and which are far more alike than different to models with ED glass, but at a fraction of their cost. These sentiments are also reflected in the models still being marketed by some big names in the large binocular world, including Celestron, Fujinon and Oberwerk. What these manufacturers offer is great performance at prices that won’t leave you out in the cold.

For certain kinds of visual astronomy, large binoculars simply can’t be beaten. The ability to use two eyes rather than one greatly influences the quality of the views, where it impacts depth of field perception, faint object detection and significant improvements in perceived contrast. Without a shadow of doubt, large binoculars are the single most powerful way to enjoy larger deep sky objects, where telescopes simply cannot offer the same ‘zoomed out views.’ That said, it’s very much a Goldilocks scenario; increase the magnification too much and you lose those gorgeous panoramic sights, but when the power is too low, finer and fainter details remain elusive. It was with this realisation that I took a punt on a curious large achromatic binocular made by Pentax; enter the PCF WP II 20 x 60.

That Pentax were prepared to put their name on the PCF WP II 20 x 60 is a lesson in objectivity. Why would such a prestigious manufacturer of high-end cameras and sports optics decide on a well-appointed, large achromatic binocular? The answer is that when well made, even a 20x model would deliver up wonderful, tack sharp views of the landscape by day and breathtaking celestial vistas by night. And this has been achieved at a price point that suits the budgets of discriminating amateur astronomers who just appreciate well designed classical optics; true observers rather than casual sightseers; folk who want real substance rather than the latest ‘gee whiz’ gimmicks.

                                                     A Full Featured Binocular

Though the instrument can be acquired at a good, price new (£219 UK for the latest SP model), I was lucky enough to acquire this binocular in excellent, used condition for a little over half the retail price. The former owner had taken very good care of it, added a sturdy carrying strap and dispensed with the flimsy carrying case, replacing it with a sturdy foam-lined aluminium case.

The Pentax 20 x 60 snug in its foam-lined aluminium case. Note the tripod adapter attached to the instrument.

The porro prism binocular weighs just 1.4 kilos (~3 pounds), surprisingly light for an instrument of these specifications and is water and splash proof. This may account for the WP(water proof?) in their name. The interior is purged with dry nitrogen gas to prevent internal fogging and to minimise corrosion.The body, which is constructed of a lightweight magnesium alloy, is covered with a protective rubberised substrate that is easy to grip and is tough and durable in all weathers.

The petax 10 x 60 is deisgned for rough weather use.

The optics are fully multi-coated to maximise light transmission to the eye and reducing contrast-robbing internal reflections to a minimum.

The beautifully applied multicoatings on the large 60mm objective lenses.

Hard coatings on the ocular lenses maximise their durability.

The centre focusing wheel is remarkable in two respects. Firstly, it is quite tight in comparison to other binoculars I’ve used. This was intentionally done by the manufacturer, as you’re not likely to use this instrument watching fast moving birds or some such, necessitating the rapid change of focus position. This increased tension does however allow for very precise focusing to be achieved. Secondly, there is a facility on the focuser to lock it in place. Simply push the focusing wheel forward and it is locked in; a nice design feature that can be advantageous. For example, if you end a session with the binocular focused on the stars at infinity, locking the focuser in place ensures that you can re-engage with the sky whenever you’re next out, with minimal (if any) re-focusing necessary.

The well designed focuser ensures very accurate focusing of the instrument and can be locked in place simply by pushing the focussing wheel forward, as indicated.

The strong bridge connecting both barrels of the binocular is reassuringly stiff, allowing one to easily obtain the correct inter-pupillary distance (IPD) and only requires occasional adjustment in field use.The dioptre setting is found under the right-hand eyecup allowing independent focusing of both barrels. It has just the right amount of tension and stays in place without any fuss.

The dioptre setting on the binocular lies directly under the right eye cup.

I really like the twist up eyecups on the Pentax PCF WP II 20 x 60. Like my smaller roof prism binoculars, they click into place and are quite secure. Eye glass wearers just need to hold the eyecups down, while those who don’t (yours truly included) can extend them upwards for very comfortable, full-field viewing. The texture of the cup is hard rubber which is a far cry from the cheap fold up/down eyecups seen on many other large binoculars in this price range. Indeed it is my experience that the latter can fragment in prolonged field use, necessitating their replacement from time to time. These sit very comfortably against the eyes and never need to be adjusted. Eye relief is exceptional; a very comfortable 21mm.

High quality hard rubber eye cups twist up and lock in place for non eye glass wearers. Those who wear eye glasses will likely keep them fully down while in use.

                                                    Mounting Options

It is not the weight per se that forces one to mount this binocular. As stated above, they are quite light for their optical specification. Rather, it is the 20x magnification that limits their hand-held use. That said, I can hold them reasonably steady by extending my hands a little further forward on the barrels than with my smaller binoculars and this strategy can work quite well for short, ‘quick peek’ sessions. Incidentally, I discovered thumb indentations on the belly of the instrument presumably designed to assist hand holding! Golly gosh!

Ain’t that sweet: indentations to fit the hand on these big binos!

Still, whatever jitter you have, it will be magnified 20 times while looking through it. Such high powered binos definitely require some kind of stablising action and, in this capacity, one can either elect to use them tripod-mounted or by using a monopod.

The Pentax PCF WP II 20 x 60 binocular can be easily mated to a light weight tripod with an appropriate adapter.

A word of caution; avoid using those cheap plastic tripod adapters that often attend bargain basement large binos such as the ubiquitous 15 x 70. These introduce an annoying level of flexure that will almost certainly detract from enjoying the instrument in the field. It is strongly advisable to invest that little bit more in a good quality, all-metal unit sold by Opticron and other companies. Indeed, I found the same adapter that fits my 10 x 50 roof prism  binocular also work swimmingly well with this larger instrument.

Tripods have their pros and cons though. Although they offer the maximum level of stability and have built in slow-motion controls on both axes, they are quite uncomfortable to use when aimed high in the sky. I found it quite hard to find a suitably comfortable positioning of my eyes when used in the seated position. That said, a trpod was useful in checking collimation of the barrels and certain daylight activities, but in the end the most suitable way I’ve found to use this instrument is by mounting it on a simple monopod.

Using a high quality(solid aluminium) ball & socket adapter, mounting the 20 x 60 on a monopod is quick and easy to execute.

Travelling light; the author’s preferred mode of mounting the Pentax 20 x 6o binocular using a light but strong extendable monopod and ball and socket head.

Simplicity itself; the 20 x 60 mounted on a lightweight but sturdy monopod.

Using the monopod, I have been able to get very stable views during daylight and extended periods of night use. For quick looks, I usually stand and adjust the angle of either the monopod itself or the ball & socket head. For the most stable viewing sessions however, I relax in a recliner and, securing the monopod base between my feet, have attained nearly jitter-free viewing. I have learned to place some of the weight of the binocular on my face, which increases the overall stability to a significant degree.

Yours truly suitably attired, demonstrating the use of the monopod.

 

Pentax PCF WP II 20 x 60 Optics

As the size of binoculars increase, it makes a lot of sense to decide on a porro prism design, rather than its roof prism counterpart. Porros are less expensive and just easier to make well and also offer slightly more light throughput than their roof prism counterparts. The optics of the Pentax PCF WP II 20 x 60 are notable. All lenses are fully multi-coated with a protective overcoat. The Bak-4 prisms are also multi-coated. The oculars are constructed from aspherical lenses which offer several advantages over conventional lens systems, espcially in the suppression of spherical aberration and a number of off-axis aberrations that plague conventional porro binos. In addition, fewer elements are needed with ashperical designs, significantly reducing weight.  Rather than rambling on with this, it’s best to hear it from an established optics firm. Here is a link to more information on aspherical lenses.

Collimation test

Collimation of binoculars is important especially on these high power units. One quick way to test for collimation is to mount the binocular on a tripod and select a target at least a kilometre away. I elected to use the snow capped Fintry Hills a couple of miles distant.  With the correct IPD selected for my eyes, I look through the binocular and slowly pull my eyes away until the exit pupils start to become separated and I can only see the top of the field. If there is miscollimation, one image will be raised slightly higher than the other. To my relief both images remained perfectly level. Testing for sideways collimation involves aiming at a distant target and testing to see if images at the edge of the field are precisely aligned on both sides. In doing this, I detected a very slight misplacement but it was so small that I wasn’t worried. The images merge very easily and you don’t encounter eye strain even after prolonged use.

Misaligned prisms can also be revealed by examining the shape and size of the exit pupil when the binocular is pointed at a source of light. As you can see below, both exit pupils are round and of the same size indicating that all was well.

Two round exit pupils of the same size indicate good alignment of the prisms with no picking off evident.

Daytime tests:

The binocular has a 3mm exit pupil. This ensures the best part of your eye is imaging the field. And oh what a field! When precisely focused images of daytime targets are bright and tack sharp across nearly the entre field (read 95%), indicating that that aspherical optics were working well. Contrast is excellent with very effective baffling of stray light. On axis, very little chromatic aberration could be detected but I could see that off axis some lateral colour was evident. That said, it was very slight and totally acceptable to my eye. In comparison to a side by side test made with my ShortTube 80 f/5 achromatic telescope charged with a power of 16x (5mm exit pupil) in a wider 3.75 degree field showed much higher levels of lateral colour.

Spying on a corbie perched on a TV aerial against a bright sky background about 40 yards in the distance showed very slight secondary spectrum around the crow’s jet black plumage. I deemed the result quite excellent and non-intrusive for an achromatic binocular of these specifications.

Close focus was estimated to be about 8.5 metres.

 

A Curious Aside: More on ED glass in binoculars here  and here. 

Nightime tets:

For nightime testing, I mounted the 20 x 60 on a simple monopod, as described previously. This is a very quick and effective way to get going with this large binocular. Some users of the instrument complained about the small field of view offered by the Pentax PCF, what with its 2.2 degree true field. Others commented on the sensitivity of the instrument to eye placement, but truth be told, I found neither of these things to be in the least bit distracting. You see, I’m used to very small fields working with close double stars at very high magnifications and with fields that are far smaller than what is offered by this big gun. Right off the bat, I was enjoying very comfortable, stable images. A 2.2 degree field is small as 60mm binoculars go, but it is plenty good enough to frame larger deep sky objects. To my mind, it simply boils down to training.

My first light target was the Pleiades cluster in Taurus. Getting myself comfortably positioned on my recliner and adjusting the monopod, I was absolutely blown away by the sight of this magnificent open cluster in the 20 x 60! More like an astrophoto than anything else, the entire cluster was beautifully framed, crammed full of gorgeous blue-white starlight and razor sharp from edge to edge. The sky hinterland was jet black with none of the flaring of stellar images that I had experienced in my brief rendevous with budget 15 x 70 models.  It is immediately apparent that the field is very flat from edge to edge, with no distortions that I could register. It just exuded quality! And although I own a number of good telescopes that can collect far more light than this 20 x 60 instrument, they could not beat it in terms of delivering such a magisterial image. Focusing the binocular was particularly satisfying; very small motions can make the difference between seeing the faintest stars and not seeing them at all.

Turning next to the Sword Handle in Orion, which is also perfectly framed in the 2.2 degree field,  I was deeply impressed at the wonderful contrast and colour rendering of the bright O/B stars in the field; tiny little pinpoints of light bathing my retinas. I could easily make out the greenish hue of the great Nebula in Orion (M42) and a steady hand revealed at least two of the tiny quartet of stars comprising the famous Trapezium (Theta Orionis complex).

Though the field of view is not large enough to frame the three bright Orion belt stars, the 20 x 60 pulls out many more faint stars in Collinder 70 that are quite beyond the reach of my regular astro binocular; my trusty 10 x 50. Suddenly, this preterrnaturally lovely open cluster has become a whole lot more crowded!

In the wee small hours of freezing January nights, I would watch the sky, waiting for the Beehive Cluster (M44) in Cancer to approach the meridian. Having experienced the Pleiades, I was very much looking forward to seeing this large and sprawling open cluster in the 20 x 60. And again, it did not disappoint; the view was enthralling! The entire field was filled with pinpoint stars against a jet black sky. Using two eyes greatly enhances the view and there is a lot to be said for seeing these wonders of God’s creation in their correct orientation, as if they were made for such instruments.

The glories of the Double Cluster in Perseus were a joy to behold in this high power binocular; great mounds of starlight of varying hues with curious fans and spirals of distant suns meandering their way from their crowded centres. Compared with a 10 x 50, the view was simply in a different league!

I didn’t notice much in the way of chromatic aberration in the images, save for a brief spell with the Dog Star, Sirius. It’s brilliant light is dazzling in the 20 x 60, corruscating with various colours from moment to moment. In my opinion, secondary spectrum is a complete non-issue with this instrument for astronomical use; just set it up and go stargazing!

Although smaller deep sky objects are best examined in telescopes with more light gathering power and their ability to take higher magnifications, I nonetheless enjoyed some very pleasing views of the Auriga trio of Messier open clusters; M36, M38 and especially the sumptuously rich M37, which appears satisfyingly large, well defined and glistening with the light of many faint suns. M35 was also big and prominent in this large binocular with dozens of its constituent stars being easily made out.

This is a wonderful instrument for framing and observing the Engagement Ring: a circular arrangement of faint stars encrusted with the creamy bright Polaris as the principal gemstone. Smaller, more conventional binoculars really don’t show this structure half as well, owing to their lower power, wider fields and reduced light grasp.

With such a large and powerful binocular, the colours of stars really stand out; marmalade orange Propus, sanguine red Mu Cephei, the soft yellow pastels of Capella and the Orion belt stars, white as the driven snow. This instrument would also make a dedicated variable star observer very happy, what with its impressive light gathering power (reaching down to perhaps + 11 magnitude from a dark site with good transparency) in a very well corrected, wide field. The 20 x 60 might not be the first instrument that comes to mind for a budding comet hunter, but I am reminded of the advice of the great 19th century observer, William F. Denning, who recommended an instrument with a field of view of between 1 and 1.5 degrees for such work. And in more modern times, the distinguished comet discoverer, David H. Levy, advises that the comet-seeking instrument deliver a field of just 0.75 angular degrees! Seen in this light, the suggestion doesn’t seem quite so far fetched.

The telescope provides wonderful views of some prominent binocular doubles; Mizar & Alcor, o1 Cygni, Albireo, Mintaka and Cor Caroli, to name but a few.

Structure within Structures

The Pentax PCF 20 x 60 is a formidable instrument for delineating structures within larger asterisms. Just have a look at the stars around fiery red Aldebaran with this bazuka! Sure, you can’t see the entire Hyades but with its pinpoint stars, wonderful contrast and generous ‘space penetrating power’, as Sir William Herschel of old liked to say,  it allows you to capture painfully beautiful starfields, rich in light and colour against a velvet black sky.  It’s even more amazing when pointed at Alpha Persei; the field is littered with lovely stellar jewels sparkling through the cold dark of interstellar space. This will be a great instrument to begin a study of stellar hinterlands around the brightest stars in general, something I thought about in the past but never pursued because of other diversions. I think it’s tailor made for such projects!

Ready to go when you are: the Pentax PCF 20 x 60 can be used at a moment’s notice between heavy showers when some clear spells manifest.

Starting in Gemini and running the binocular haphazardly across the sky through Auriga, northern Orion, Taurus, Perseus and ending in the gloriously rich Cassiopeia, the binocular shows me many new asterisms which I had not witnessed before, a consequence of its unique field of view, magnification and image orientation. Almost every field stumbled upon brings new bounties, delicate arrangements of stars unnoticed in smaller binoculars; vast shoals of starlight in the open ocean of space.

Moon Watching:

In the early days of February 2019, I got several opportunities to observe the waxing crescent Moon through the monopod-mounted Pentax PCF 20 x 60 binocular. The views were amazing; razor sharp, beautiful contrast, most excellent suppression of internal reflections that can easily plague lesser binoculars. Indeed, I’ve devised this simple but highly discriminating test as a way to quickly establish whether a binocular is fit for general astronomy use. If the unit shows flare and/or internal reflections when pointed at the Moon, it’s leaking light.

The image scale of the Moon seemed larger than I expected it to be in going from a standard 10x binocular to this 20x unit. It just seemed like I was getting a higher power than the 20x marked on the Pentax binocular tube. This is no doubt an illusion, a consequence I suppose of the Moon’s taking up a larger fraction of the area of the field than seen in my trusty 10 x 50 binocular.

The earthshine from the dark side of the Moon was very prominent and as the crescent continued to grow, the binocular revealed more and more details of the lunar regolith. The image scale is great for seeing high resolution details of the battered southern Highlands. On the evening of February 10, I enjoyed a wonderful view of the three large craters; Theophilus, Cyrillus and Catharina on the eastern shore of Mare Nectaris. Up north, Atlas and Hercules could be clearly made out with a steady hand. The limb displayed a sliver of colour; sometimes green, sometimes yellow, depending on where my eyes were postioned.I judged the chromatic aberration on this tough target to be minimal and completely non-intrusive to a seasoned telescopic observer. Contrast between the bright lava fields and darker maria was very well presented, producing an extremely immersive, aesthetically pleasing view.  This will be a great binocular to observe the early waxing Moon during March and April, when earthshine is at its most prominent and I look forward to fielding the instrument for this purpose. Sure, the binocular cannot substitute for the telescope proper, but it certainly complements those high-power, high-resolution views. The big binocular has a charm all of its own and should really be enjoyed on its own terms.

Concluding Remarks:

A quality, large binocular at a great price!

As you can probably discern from the above write up, I took to this instrument like a proverbial duck to water!

The Pentax PCF 20 x 60 WP II  is an impressive performing, large binocular, with a rugged but durable housing. It is water and splash proof, making it suitable for routine and/or prolonged work by day or by night. Its high magnification requires a stable mounting system to get the best out of the instrument.The ability to lock the focus in place is a useful mechanical feature that will be greatly appreciated by all those who use it in the field.

The Pentax 20 x 60 has very high quality optics, including properly collimated porro prisms and quality multi-layer coatings that efficiently transmit light to the eye. All lenses are also fully multicoated. The aspherical optics deliver a very highly corrected field, from edge to edge. Chromatic aberration is very well controlled and is not intrusive in normal use. Contrast-robbing internal reflections are also very well suppressed in this instrument. The binocular is very easy to use and has comfortable eye relief(21mm with the twist-up eyecups), allowing hassle-free viewing for both non eye-glass wearers and those that like to observe with their glasses on.

Less experienced observers have complained that the binocular has too small a field, but I am reminded of the superbly designed (but very expensive!) Takahashi Astronomer 22 x 60 binocular which sported a field of view of just 2.1 angular degrees, so slightly smaller than that offered up by the Pentax 20 x 60! In truth, a 2.2 degree true field is perfectly adequate to frame the vast majority of celestial objects.

The binocular is ideally suited to framing showpiece deep sky objects for careful study, such as the Double Cluster, the Pleiades, the Beehive Cluster and other large Messier objects, but is also well appointed for use in comet hunting/observing and variable star work. Its high magnification and excellent contrast produces magnificent views of the Moon that will impress anyone who uses it.

The Pentax PCF 20 x 60 WP II can also be employed as a two-eyed spotting ‘scope in long-distance daylight viewing/surveillance, e.g. observing a bird’s nest at a comfortable distance or in a variety of maritime applications.

Its very reasonable retail price makes this a most attractive instrument for budget conscious amateurs who do not want to compromise on optical performance.

Highly recommended!

Post Scriptum: Stephen Tonkin, an accomplished binocular astronomer and author has written another review of this binocular (the newer SP incarnation). It can be viewed here.

 

Neil English is the author of several books on amateur astronomy. His latest work, Chronicling the Golden Age of Astronomy, is now availlable in hardback and electronic formats.

 

De Fideli.

8 Spectacular Binocular Sights for Winter Nights.

Out and about with my 8 x 42 binocular.

 

The winter sky is jam packed full of beautiful sights that can be appreciated with ordinary binoculars. Many of the brightest stars in the sky sparkle through the darkness on winter evenings, and some of the best open clusters and nebulae make their presence felt to even a casual observer even with the most basic of optical aids. In this blog, we shall explore 8 spectacular sights that can be enjoyed with hand-held instruments or using simple, stabilising arrangements such as a monopod.

Solid as a rock; the 10 x50 binocular on a monopod.

All of the targets in this article were observed with modest 8 x 42 or 10 x 50 roof prism binoculars, serving up fields of 8.2 and 5.9 angular degrees, respectively; plenty wide enough to see all of the targets discussed.  What follows is a series of concise notes on what can be expected from a dark rural site with these instruments, but those who live in large towns and suburban areas can also enjoy many of the same sights. So what are you waiting for? Fetch your warm winter coat, hat and gloves and join me on a whistle stop tour of the winter binocular sky.

Exhibit 1: The Pleiades/Messier 45/Seven Sisters.

Location: Northwestern Taurus

The main part of the beautiful Pleiades cluster, as observed through 8 x 42 and 10 x 50 binoculars, based on observations taken over several evenings in early January 2019.

Easy to find with the naked eye on winter evenings, the Pleaides is one of the most beautiful and engaging targets in all the heavens. This wondeful asterism consists of over 100 stars scattered across 1.5 angular degrees of sky. My wide angle 8 x 42 shows many of the brightest members, which shine with either a white or blue-white hue against a velvet black sky. Many wonderful stellar associations can be feasted on; doubles, triples and elaborate curving arcs of stars that fan their way from the bright centre of the cluster. My 10 x 50 binocular, stablised on a lightweight monpod, significantly enhances the view with its larger image scale and ability to pull out fainter members. Words cannot fully grasp the beauty of this winter treasure. Small wonder the Pleiades has been the stuff of poetry ever since mankind first gazed upon the heavens. Clean, dust-free optics produce the prettiest views, minimising the scattering of light from its brightest members. Indeed, dusty optics can cause some individuals to mistakingly report seeing the faint reflection nebula around Merope and Alcyone with binoculars of this size, but in reality significantly larger instruments and exceptionally clear and transparent conditions are required to pull out this feature from the pretty asterism. This loosely bound system of stars is estimated to be about 50 million years old, with many of its main stars located about 440 light years from the solar system.

Exhibit 2: Praesepe/Beehive Cluster/Messier 44

Location: Central Cancer

Praesepe; the celestial Manger with Beehive Cluster (M44) seen left of centre.

On a dark, moonless night, cast your gaze between the constellation of Gemini in the west and Leo Major in the east, just north of the ecliptic, and you’re sure to chance on a large foggy patch situated between Delta and Gamma Cancri. Binoculars will unveil a stunning sight; a beautiful quadrilateral of bright stars with a vibrant stellar cluster just left of its centre. Arriving on the meridian late on January and February evenings, the quadrilateral delineates the manger in which the Christ child was laid, with the cluster itself presumably denoting the spot where the holy family lay resting.

The cluster itself is more famously known as the Beehive (Messier 44); an entirely appropriate appellation for this magnificent binocular sight. Several dozen stars are brighter than magnitude 6 but many of these are too close to each other to be cleanly resolved in ordinary binoculars. The cluster contains many fainter members, though while remaining unresolved, contribute a lot of diffused light which greatly enhnaces the visual appearance of the spectacle. Better seen in 10 x 50s than 8 x 42s, the manger structure is lost in the smaller field offered up by larger binoculars, though the cluster stars will be enhanced.The Beehive contains a total of about 200 stars and lies about 590 light years away.

Exhibit 3: Collinder 70

Location: Orion

Collinder 70, of which the three belt stars of Orion are the brightest members.The arrow indicates the rough position of Eta Orionis, for perspective.

Our next target couldn’t be easier to find. Simply point your binocular at the belt stars of Orion (from east to west these stars are called Alnitak, Alnilam and Mintaka), which radiate with an intense, white hue, pure as the driven snow. But the belt stars are merely the brightest members of a far grander cluster of magnitude 6, 7 and 8 stars collectively known as Collinder 70, snaking their way up and around them. For best results, observe this cluster when the Moon is out of the sky and when Orion reaches its maximum altitude in the south. I’m in two minds about which binocular yields the better view. The 8 x 42 yields a whopping 8.2 degree field giving a wonderful wide-angle perpective, while the 10 x 50 shows some fainter members but in a smaller true field. For this object, I think I’ll give the nod to the former instrument.Where I’m located at 56 degrees north latitude, Orion never gets too high in the sky, and I find it interesting to see how the view improves- a darker sky with more numerous stellar members – as the constellation wheels its way toward the meridian. Each incremental rise in altitude; degree by degree; enhances the view. This is a delightful target for all lovers of the night sky. Don’t leave winter behind without a visit!

Exhibit 4: Melotte 20/ Alpha Persei Association

Location: Perseus

Melotte 20 centred on Alpha Persei(Mirfak). The stars are arrayed south to north, as it appears in late winter.

On a dark, moonless night with good transparency, the constellation Perseus looms high in the sky for northern observers. Our next port of call couldn’t be easier to locate; just point your gaze at Mirfak (Alpha Persei) and hold up your binocular to your eyes. The scene literally explodes with beauty! A torrent of starlight drowns your eyes, as the wide field view of the binocular captures the riot of stellar members in this famous OB Association. In late autumn and early winter, Perseus climbs the vault of the sky from the east, presenting its stars in an east to west orientation, but I have found that the view is that little bit more magnificent when it sinks into the western hemisphere on January evenings, when the same stellar association is arrayed north to south, when the above sketch was made. Containing about 70 hot white and blue-white stars ranging from magnitude 3 through 10, Melotte 20 is quite young; about 50 million years old with the main members being located some 550 light years from the solar system. This author never tires of its beauty; the more you look at it, the more you see!

Exhibit 5: The Hyades/ Melotte 25

Location: Taurus

The Illustrious Hyades; eye candy for ordinary binoculars.

To find our next winter binocular treasure, just cast your gaze on the beautiful orange star, Aldebaran, and bring your binocular to your eyes! Aldebaran is the brightest star of the familiar horns of the Celestial Bull. But with the aid of binoculars, your eye can feast on a sparkling array of double and triple stars of varying glory and hue. Best framed in a 10 x 50 binocular, the cluster spans a whopping 5.5 degrees with as many as 130 or so stars presenting as brighter than magnitude 9. Intriguingly, Aldebaran is not a true member of this system but is actually located about half as far away as the other stars in this sprawling open cluster, which astronomers estimate is about 150 light years away. Few binocular sights enthrall as much as the Hyades. I love the way the cluster changes its orientation in the binocular field as it transitions from the eastern to the western hemispheres of the sky. Using a monopod with the 10 x 50 helps bring out the faintest members that often elude hand held observations.

Exhibit 6: The Double Cluster/Caldwell 14/h & Chi Persei

Location: Perseus

The celebrated Double Cluster in Perseus; eye candy for all apertures.

Our next target is very easy to find; just look midway between the ‘wonky W’ of Cassiopeia, the Queen, and the ‘tip’ of Perseus, the Hero. From a dark, country sky, devoid of moonlight, these clusters are clearly visible to the naked eye as an elongated foggy patch, but turn a binocular on them and you’re in for a real visual treat! Both clusters are about the size of the full Moon and are designated NGC 884 and NGC 869. The richer of the two is NGC 869 (western most) and contains about 200 stellar members, while the eastern-most cluster (NGC 884) has stars that are significantly more scattered. Together they provide a breathtaking sight in ordinary binoculars. The above sketch was made with a 10 x 50 instrument and covers a swathe of sky roughly 5 angular degrees in extent. An eye-catching stream of stars is seen fanning away from both clusters. From high northern latitudes, the Double Cluster is well placed for observation from early autumn through early spring but is best observed when it is highest in the sky after sunset on December and  January evenings. Both clusters are located some 8,000 light years away and consist of mostly young type A and B stars, though larger instruments will help pull out more highly evolved, ruddier members.

Exhibit 7: The Sword Handle of Orion

Location: Orion

The Swordhandle in Orion as seen in my 10 x 50 binocular. The field covers an area slightly larger than 2 angular degrees in width.

Our next target is the Swordhandle of the great constellation of Orion, readily identified with the naked eye even from an urban setting. This is a spectacular sight in any binocular but is especially pretty in a 10 x 50. The eye is immediately drawn to the Great Nebula (M42), one of the nearest star forming regions to the solar system. Newborn stars light up the gas and dust surrounding them and a steady hand will reveal several pinpoint stars within its confines. Just above it lies M43, just separated from M42 by a thin sliver of dark sky. At the top of the field is the pretty open star cluster, NGC 1981 and below it the binocular picks up some faint whisps from the diffuse nebula NGC 1973-77-79. Below M42 lies the comely binocular double star Iota Orionis and Struve 747 which appear to have some nebulosity associated with them. I have no trouble seeing a greenish colour in M42 in larger binoculars or in my 80mm f/5 refractor at medium power, but I find it somewhat elusive in the 10 x 50. Perhaps those observing from a darker site may fare better in this regard. Many of the objects in the sketch are located between about 1200 and 2,300 light years from the solar system.

Exhibit 8: Melotte 111, the Coma Star Cluster

Location: Coma Berenices

The widely spaced Coma Star Cluster as seen in the author’s wide-angle 8 x 42 binocular.

Our final target is for night owls – the celebrated Coma Star Cluster in Coma Berenices – as it doesn’t culminate until well into the wee small hours during early February. Those who prefer to observe earlier in the night might wish to wait until month’s end to explore it. To do justice to this large and sprawling open cluster, a wide angle binocular is the best tool, as the cluster extends over a broad swathe of sky (at least 6 degrees) and is completely lost using telescopes. My 8 x 42 nicely frames this very loose congregation of suns, the brightest of which are of the 5th magnitude of glory. Visually striking, the main feature of this cluster is a distorted ‘V’ shape which renders it rather easy to identify with optical aid. The Coma Star Cluster(not to be confused with the galaxy cluster bearing the same name), with its 50 or so members, is close to the solar system as clusters go; just 285 light years according to the best modern estimate.

Water for the Soul:

Well, I hope that you will take the time to venture out on these long winter evenings to observe these beautiful and accessible objects. You don’t need any fancy equipment, just ordinary binoculars, a warm coat and hat, and a modicum of curiosity!

Thanks for reading and clear skies!

Neil English is the author of a new and ambitious historical work, Chronicling the Golden Age of Astronomy, now available in hardback and electronic formats.

 

De Fideli.

A Survey of Binocular Astronomy Literature.

Every dedicated binocular enthusiast needs a good binocular guide.

Dedicated to Steve Coe (1949-2018)

As an enthusiastic, life-long collector and reader of astronomical literature, I’ve always appreciated the power and value of the printed word.

Having re-ignited a keen interest in binocular observing, I was somewhat saddened to see that many great works of binocular astronomy were being largely ignored by amateurs. To help redress this balance, this blog will take a close look at a number of books dedicated to the art of visual observing using ordinary binoculars, where I offer short reviews of a number of inexpensive works. Their value lies in the collective knowledge of the authors who have produced these works; experience that far exeeds those offered by the self-proclaimed ‘experts’ constantly chattering on internet forums. And you will save yourself a small fortune – time and money – by heeding their advice.

Exhibit A: Discover the Night Sky through Binoculars: A Systematic Guide to Binocular Astronomy.

Author: Stephen Tonkin

Publisher: BinocularSky Publishing

ISBN: 978-1-9164850-0-6

Price: £10

1st edition: October 2018, pp 145.

Want a good binocular guide for Christmas? I have the perfect recommendation for you! Stephen Tonkin’s new book is sure to appeal to binocular enthusiasts of all ages. Tonkin is no flash in the pan. He has authored or contributed to many books I’ve acquired over the years and writes a monthly column on binocular astronomy for Britain’s BBC Sky at Night magazine. He also maintains an excellent website dedicated to binocular astronomy, which can be accessed here.

So I was in no doubt about my expectations concerning his new offering and boy does it deliver! Though it looks like a self-published book, Discover the Night Sky through Binoculars, is a witty and authoratative survey of what can be realistically achieved with binoculars. After a short introduction, the first three chapters cover all the technical stuff you’re likely to need to know about how to get the best out of a decent binocular. There is a particularly humorous mention of some rubbish models, which Tokin refers to as “binocular-shaped objects.” He avoids making specific recommendations about specific models though, which is a good thing, as many units can now be purchased fairly inexpensively that can provide a lifetime of great astronomical views.

The remainder of the book is divided up into the many binocular sights arranged in a month by month sequence. His superlative first-hand knowledge of the heavens shines through as he clearly and effectively shows the reader how to locate each target. All the showpiece binocular targets are covered in this book, and many more besides. Though the sky maps printed in the book are a bit small to see well, one can always download higher quality maps from his website which you can study at your own leisure. I love his description of a phenomenon called pareidolia, which describes the psychological condition of seeing patterns in the starry heavens that are not really there!

I spotted one howler though; on page 8 he says, “our visual system evolved using two eyes.” Mr.Tonkin ought to look at this presentation by an expert on human vision before jumping to such conclusions! Tut tut lol.

It’s very easy to use this book, especially if you already have some experience of the night sky, but it will work equallly well for newbies. Indeed, it’s almost like having an expert right beside you as you make your own binocular observations. The end of the book features several useful appendices, whch cover important topics, such as how to determine the size of your dilated pupil, how to test your binocular for defects, as well as sound advice on how to maintain your binocular in tip-top condition over the months and years.

This is a great, no-frills book, with simple black & white illustrations, but it’s packed full of excellent observing projects that will keep you blissfully happy for many years to come.

Exhibit B: Binocular Highlights: 109 Celestial Sights for Binocular Users

Author: Gary Seronik

Publisher: Sky & Telescope

ISBN: 978-1-940038-44-5

Price: £18.99

2nd Edition 2017, pp 112.

Gary Seronik is no stranger to those who have enjoyed Sky & Telescope magazine over the years. He wrote a regular column; Binocular Highlights; for Sky & Telescope between 1999 and 2016, where he thereafter became the editor of the well regarded Canadian astronomy periodical, SkyNews. This neat little book features 109 objects from all over the northern sky that can be enjoyed with binoculars. After a good introduction, Seronik summarises all the things you need to know about binoculars and makes a specific recommendation that a 10  x 50 unit is probably the best compromise between power and portability. That said, he admits that he is an avowed fan of image stablised models, such as his favourite; a Canon 8 x 42IS.

The remainder of the book is divided up into chapters covering the four seasons of the year, where he presents a series of brief but very engaging mini-essays on the most celebrated of all binocular targets, concentrating on those objects that are best seen from mid-northern latitudes, though he does have an occasional entry of sights only visible in the deep south, such as the illustrious Omega Centauri. The book is lavishly illustrated throughout, with full colour charts typifying a 10 x 50 binocular view, on pages made from thin cardboard rather than regular paper, and is ring bound for convenient use in the field.

If I have any quibbles to make about this book, they are minor; I just wish he could have included more objects. That said, I suspect that, for the vast majority of observers, yours truly included, binocular observing is not really about pushing the envelope to observe overly difficult or challenging objects. The targets themselves are so beautiful that you’re likely to observe them many times during a season, where their orientation in the binocular field changes as they wheel across the sky. Thus, Binocular Highlights is designed for observers who just enjoy looking at the same objects as the season’s progress; and that’s fine.

Now in its second edition, Seronik has added 10 new entries over the original book, which is a bonus. In short, you can’t go wrong with this excellent little field guide but all the while, I can’t help but think those lovely coloured charts go a bit to waste when manhandled in the field.

Exhibit C: Stargazing with Binoculars

Authors: Robin Scagell & David Frydman

Publisher: Philips

ISBN: 978-0-540-09022-8

Price: £13.74(second edition)

1st edition, 2007, pp 208.

It is oft stated that the best way to start out in the fascinating hobby of astronomy is to purchase a good binocular. There is a great deal of truth to this sentiment. Many folk who express a casual interest in stargazing quite often become disillusioned by it, perhaps because they live in a heavily light polluted location, or they made the mistake of purchasing a large, complicated telescope that is just a pain to set up in the field. The wonderful thing about binoculars is that they are much more versatile than dedicated astronomical telescopes, since they can be used during the day to have a good look around, for nature treks, birding, camping, watching sports and the like.

Stargazing with Binoculars takes a much more pedestrian path through the fascinating world of binocular observing. Written by two veteran stargazers, Robin Scagell and David Frydman, who have amassed an enormous amount of field experience with more binoculars than you could shake a proverbial stick at. Their book, now in its second edition, shows you how the sky works and then presents a month by month overview of what can reasonably be seen using binoculars of various sizes. Unlike the aforementioned books, the authors include sections on lunar, planetary and solar observing, before engaging in a comprehensive survey of the binocular market. This is a great book to learn about how binoculars are made, what the various models offer the observer and how to test binoculars prior to purchasing. It also features an excellent chapter on how best to use a given binocular; whether it be hand-held, harness stabilised, or securely mounted in a variety of configurations, from simple monopods to complex binocular mounts.

Stargazing with Binoculars provides a wealth of information that any interested reader will find useful, including how to estimate binocular fields using star tests, making sketches of what one sees in a binocular, as well as sections on observing comets, meteors, artificial satellites and much more besides. It also provides a comprehensive overview of the southern sky, so it is equally useful to those observers who enjoy life in the antipodean.

This is a fabulous, cost-effective book for all binocular enthusiasts, featuring a generous number of full colour images to complement the text, and although I have not seen the second edition( 2013), I’m sure it will be just as good if not better. All in all, a great stocking filler for the binocular enthusiast!

Exhibit D: Observing the Night Sky with Binoculars: A Simple Guide to the Heavens

Author: Stephen James O’Meara

Publisher: Cambridge University Press

ISBN: 978-1843155553

Price: £24.99

2008, pp 148

I’ve always been a fan of Stephen James O’ Meara, a highly accomplished visual observer, who served on the editorial staff of Sky & Telescope for many years before joining Astronomy(USA) as a regular columinist. I have collected and enjoyed all of his books over the years and would heartily recommend them to anyone.

Though he is perhaps better known for his studies of deep sky objects, observing from the big Island of Hawaii using 4- and 5-inch refractors, I was glad to see that he produced a book dedicated to binocular observing to complement his telescopic adventures.

Observing the Night Sky with Binoculars is a large book compared with all the others mentioned above, with dimensions of 12 x 8″. The book opens with a great introduction to exploring the night sky, featuring the Big Dipper as a starting point to find your way around the sky. Here, you’ll learn how to estimate angular separations between objects, how best to perceive star colours, as well as a good introduction to the physiology of the human eye. A surprising amount of information can be gleaned by studying the Big Dipper and how it points to many other interesting objects nearby in the sky. What is somewhat surprising about this work is that O’ Meara categorically states that he used inexpensive binoculars – 7 x 50s and 10 x 50s – in preparing the material for this book. He does not dwell on the intricacies of binocular construction or advocate any particular brand of binocular, in contrast to his other books, where he strongly advertises the virtues of small, expensive TeleVue refractors(been there, done that, not going back).

The book continues by taking a seasonal look at the treasures of the binocular sky, covering each season from spring, summer, autumn and winter. What is immediately obvious is that O’ Meara has an encyclopedic knowledge of the mythology of the heavens, with a particular interest in ancient Egyptian sky lore. While this is all very good, I personally would have liked less discussion on mythology and more about actual observing, but everyone has their own take on how best to present the wonders of the night sky and, in this capacity, O’ Meara carries his own torch.

All the illustrations in this book are black & white, but the charts and diagrams are very easy to read and assimilate. In addition, there is a wealth of good drawings made by the author in this book which greatly adds to the value of this work and while many targets can be seen by the averagely keen eye, some are very challenging, requiring both very dark and transparent skies and a very keen eye to fully appreciate.

Though it is a bit more pricey than the other books discussed above, anyone with a keen interest in the binocular sky will appreciate this very well written book, and I for one feel fortunate indeed to have a copy in my personal library.

Exhibit E: Handbook of Binocular Astronomy: A complete guide to choosing and using binoculars for astronomers – whether beginners or not-so-beginner.

Author: Michael Poxon

Publisher: Starman Books

ISBN: 97809562394-0-2

Price: £12.96

2009, pp 397

Now for something completely different!

Michael Poxon is a name unknown to me, but that ought not deter a curious individual from investigating a book. Often times, to my growing knowledge, it’s ordinary folk who come across as being the most sensible and the most experienced, as opposed to the loud-mouthed guffaws you see on internet forums.

And Poxon puts his all into this very large book!

It begins, as all the others do, by stressing how important binoculars can be to the novice and dedicated astronomer alike. He offers sage advice in purchasing a good binocular, you know; what to avoid and what not to avoid. Curiously, he advises against image stabilised binoculars for the following reasons; they’re often very heavy(over a kilogram) and so do nothing to stave off arm ache, they rely on battery power(which he finds to be a nuisance) because they lose their charge in a few hours. They are also very expensive and the author feels that the money is better spent on conventional optics. Furthermore, he rightly points out that better stablisation can be achieved by using a homemade monopod. In this, I wholeheartedly agree; my brief experience with an image stabilised unit a few years back left me feeling a little underwhelmed and I felt the images were, let’s say a tad “artificial.” And although Poxon certainly advocates the cheap and cheerful porro prism varieties, he also sings the praises of compact, roof-prism models because of their labour-saving low mass in comparison to the former, albeit at some additional cost to the consumer. It is also clear that Poxon is a highly seasoned enthusiast, who has travelled to many places around the world to observe the binocular heavens. Ever the practical man, he has the presence of mind to include the construction of effective, low-tech dew shields for his 10 x 50s used during his prolonged binocular surveys, which he often mounts astride his 36cm telescope.

Chapter 2 deals with the basics of the celestial sphere, the magnitude scale of stars, as well as a very useful table indicating the magnitude limits, field of view and angular resolution of various popular models used by the amateur community. He also offers up valuabale advice on how much one can gain in stabilising a binocular; on page 31, for example, we learn that one can go a hefty 1.5 magnitudes deeper on a stabilised system compared with hand holding; and I’d call that signficant!

What follows are excellent general overviews of the Sun, Moon and planets, eclipses etc. Poxon does an especially good job in helping the reader recognise the many lunar craters and mountain ranges within the resolution remit of a typical 10 x 50 binocular with simple but very effective lunar maps. In Chapter 5 (which is mistakenly printed as Chapter 3), he delves into the fascinating world of deep sky astronomy and what follows is a very impressive listing of interesting variable stars, double and multiple stars (both wide and close-in) as well as a treasure chest of deep sky objects from the entire pantheon of constellations in the sky( the whole 88 are represented).The data is arranged in the form of notes which can be easily followed by the interested observer.

While the illustrations are not of the highest quality, they are generously presented and can be followed without much fuss. The end of the book contains a series of useful appendices with particular emphasis on variable star monitoring.This is an excellent book and, true to its opening lines, has something for every level of enthusiast; from newbie to veteran. I was pleasantly surprised by its excellent content, written by a well heeled amateur.

Exhibit F: Deep Sky Observer’s Guide

 

Author: Neil Bone

Publisher: Philips

ISBN: 0-540-08585-5

Price: £9.99

2004 pp 223

An honorary mention. The late Neil Bone(1959-2009) was a highly accomplished deep sky observer, public speaker and writer. A microbiologist by profession, he spent many of his evenings observing the glories of the deep sky from his Sussex home. Despite his notoriety and universal respect by the British astronomical community, Bone used simple equipment throughout his life, which included a ShortTube 80, a 10 x 50 binocular and a small Dobsonian telescope to accomplish all his observing goals. Deep Sky Observer’s Guide is a wonderful little book for beginning stargazers, featuring a rich selection of deep sky objects that are accessible to anyone with the same equipment. The first two chapters cover the basics of deep sky observing, including a great overview of the celestial sphere as well as the equipment and observational skills amateurs use to good effect to divine its many secrets. The rest of the book has chapters dedicated to particular deep sky real estate, including galaxies, asterisms, globular clusters, diffuse nebulae, open clusters, planetary nebulae and supernova remnants. Although the book is not about using binoculars per se, Bone used his 10 x 50 to make excellent observations of many of his subjects and are preserved for posterity in the pages of this literary gem. To see just what can be accomplished with a humble 10 x 50 binocular, this now classic text is a great place to spend some time. Many of the deep sky objects he describes were observed using his trusty binocular, and despite his premature passing, his rich word pictures still have the ability to inspire me. In amatam memoriam.

 

 

Exhibit G: Binocular Stargazing

Author: Mike D. Reynolds

Publisher: Stackpole Books

ISBN: 978-0-8117-3136-2

Price: £5.99

2005, pp 213

 

Mike D. Reynolds is a name familiar to many American and Canadian observers. A professor of astronomy and Director Emeritus at Chabot Space & Science Center at Oakland, California, he is probably best known for his popular writings in Astronomy Magazine, as well as his excellent books on eclipses and meteor watching. Binocular Stargazing is a very well written and thought-out book, covering a lot of ground. After a short foreword from celebrated comet discoverer, David H. Levy, the first three chapters provide all the information you’re likely to want to know about binoculars, past and present, written in a friendly yet authoratative style. What is very refreshing to see in this title is that, like nearly all the other authors of binocular astronomy, Reynolds emphasises that one can obtain excellent results with only a modest investment; a philosophy yours truly also shares.

Chapters 4 through 7 offer excellent overviews of how binoculars can be used for lunar & solar observing, before engaging in a thorough but non-technical treatise on the wider solar system objects, the distant stars, as well as presenting a great introduction to deep sky observing. One slight niggle pertains to the author’s persistent use of the term “pair of binoculars” throughout the book. Though certainly not a big deal and still used my many observers, the phrase doesn’t really make a whole lot of sense. The word ‘binocular’ implies duplicity. Better to use ‘binocular’ to refer to a single instrument and ‘binoculars’ when referring to more than one such instrument.

Chapters 8 through 12 offer up one of the best surveys of the binocular sky I’ve seen, arranged in seasons, ending with a special chapter devoted to observing from southern skies. Throughout, Reynolds displays his first-hand experience in the field and has a talent for making the subject matter very accessible. The science presentation is first-rate, as one would expect from a guy with an advanced degree in the science. Variable stars are particularly well represented in this title.

What I particularly liked is the inclusion of extensive appendices (A through I) at the back of the book. One appendix in particular, emphasises the age-old tradition of note-making and keeping, sketching and the like; an activity of great importance even in this age of instant digital gratification.

The text is quite generously illustrated in monochrome, though some of the images could have come out better, they are certainly good enough not to distract or confuse the interested reader. All in all, Binocular Stargazing is a highly recommended book for binocular enthustiasts, and I for one will continue to enjoy dipping in and out of it in the future.

Exhibit H: Touring the Universe Through Binoculars: A Complete Astronomer’s Guidebook.

Author: Philip S. Harrington

Publisher: Wiley

ISBN: 978-1620456361

Price: £18.34

1990, pp 306

It is hard to believe that nearly 30 years has gone by since the publication of Philip Harrington’s, Touring the NIght Sky with Binoculars. Back then, I was still an undergraduate with only a 7 x 50 porro prism binocular and a 60mm classic refractor to explore the night sky. Pluto was still a planet and the first CCD imaging pioneers were beginning to tinker with their crude chips to obtain electronic images of the celestial realm; most were still using photographic film. And while amatuer astronomy has changed beyond measure in only three decades, Harrington’s book provides solid evidence that some texts will never go out of fashion.

The preface of this now classic text reveals the modus operandi of the author, who admits that the book was primarily written for himself! Giving an honourable mention to Garrett P. Serviss’ 1888 work, Astronomy with an Opera Glass, Harrington weaves together an enormous body of field knowledge, which both complements and far exceeds the collective wisdom of his distinguished Victorian predecessor.

Harrington was one of the earliest amateur astronomers to call attention to the considerable advantages of using two eyes, explaining that gains of up to 40 per cent can be achieved in resolving fainter, low-contrast deep sky objects. This much is made clear in the short introduction to the book, but the march of time has thoroughly vindicated his binocular evangelism, as evidenced by the great popularity of binoviewing, as well the growth of binocular astronomy in general among the global amateur community.

The book, as Harrington makes clear, is actually a collection of concise notes which he himself compiled in his adventures under the night sky. Eschewing any discussion on equipment, the author launches into fabulous discussions of the Moon, Sun, planets and minor bodies of the solar system, before wading into the pantheon of objects existing far beyond our shores. Beginning in Chapter 7, Harrington provides concise but highly accurate depictions of a sumptuous listing of deep sky objects:- stars, open clusters, nebulae and galaxies, as seen in a variety of binoculars, both large and small.

In a departure from most other authors, Harrington recommends the 7 x 50 above the 10 x 50 as the best all round instrument for hassle-free binocular observing, but it is also evident that he has gained a considerable amount of experience behind a larger 11 x 80 instrument. Every constellation in the heavens is discussed separately, rather than approaching the subject from a season by season perspective. This works supremely well, being more reminscent of Robert Burnham Junior’s three volume work, Burnham’s Celestial Objects, than anything else.

While this hardback text was not designed to be used in the field, it is an indispensible work for planning and reflecting upon the sights seen on a clear, dark night. I find myself using it to compare and contrast it to my own observations and notes and to challenge myself to see more with a given instrument.

Remarkably, any discussions on binoculars per se are reserved for short appendices at the back of the book. Like all truly seasoned observers, Harrington avoids making specific recommendations, emphasing that one can do a great deal with modest equipment. Appendix B in particular, discusses how resourceful amateurs have hobbled together exceptional mounting strategies that greatly increase the comfort of viewing through truly giant binoculars, featuring such individuals as Norm Butler, Jerry Burns and John Riggs, to name but a few.

Although technology has certainly moved on (just look at the quaint photographs used to illustrate the text!) since Harrington first collated the work for this text, it is unlikely to be superceded by anything in the modern age. Indeed, it remains, for me, the definitive volume of binocular astronomy and shall continue to hold a special place in my astronomical library. Thoroughly recommended!

Concluding Words:

Just like in the case of telescopes, we are fortunate to live at a time in history where quality binoculars can be had for relatively small amounts of money. There is a bewildering number of models available to suit everyone’s budget, and even the least expensive units are immeasurably superior to the naked eye. But as all the authors of these books make clear, what is most important is that one gets out under a starry sky and use the instrument. Of course, one can decide to avoid the collective wisdom of these writers, but it will most likely lead the researcher down many dead ends (I speak from the well of my own experience), where one is tempted to keep buying ever ‘better’ models in the mistaken belief that grass is really greener on the other side. Unfortunately, this is largely the state of affairs on our telescope and astronomy internet forums, where folk seem to be more interested in a said instrument than actually using it. This is highly regrettable; indeed it is a very real kind of poverty, missing, as it were, the woods for the trees, but it can easily be countered by just getting on with the equipment we have.

I hope you have found these mini-reviews of some use and I do hope that amateurs everywhere will avail of these well thought out resources, written by people who have a real passion for observing the night sky and for sharing their knowledge with others.

Postscriptum:

Was it something I said?

Folk fae the fora having a guid chinwag about ‘binocular’, ‘pairs of binoculars’ etc.

Changin’ culture ken.

De Fideli.

 

 

Another Binocular Review: The Barr & Stroud Savannah 8 x 42 Wide-Angle.

One of the best on a budget: the Barr & Stroud wide angle Savannah 8 x 42 roof prism binocular.

 

What’s in a name?

I found myself asking this question after taking a chance on a number of decently priced roof prism binoculars made by Barr & Stroud, which completely surprised me. Barr & Stroud have long since ceased from trading as an independent company but a name remains valuable, that’s for sure. Perhaps it’s the know-how they leave with the parent company who buys them out? Maybe it’s the work ethic associated with the name? Whatever it is, they sure know how to put together a quality optic!

My evidence for this rests in three binoculars I’ve tested from the line offered by Barr & Stroud; the Sahara 8 x 42, the Sierrra 8x 42 , and a larger instrument, the 10 x 50 Sierra used exclusively for astronomy. Indeed, user reviews of these instruments seem to be almost universally favourable, with many claiming that they shoot well above their weight, especially for their modest price tag. The experience with these units confirmed a suspicion I have entertained for quite some time; that in this day and age there is no need to opt for premium models costing upwards of £1000, as quality has improved so much as to render them largerly unnecessary for the vast majority of enthusiasts. Excellent optics need not cost the Earth.

I chose the 8 x 42 roof prism binocular because of its compactness and rugged design that is less prone to mis-alignment than the equivalent porro-prism models being offered. It is the ideal cross-over binocular, allowing one to enjoy fabulous views of the landscape by day and very satisfying casual observation of the heavens by night. The 8 x 42 reigns supreme among birders and hunters for some years now, as its decent light gathering power and ultra-portability allows viewing objects under low light conditions, as is often experienced at dawn and dusk, as well as the failing light of mid-winter.

I have been blissfully happy with the Barr & Stroud 8 x 42 Sierra, as it seemed to offer all the things I wanted in a versatile, multi-purpose binocular, but I was still highly intrigued by yet another model marketed under the same brand name which seemed to be garnering even better reviews from consumers; enter the  8 x 42 Savannah.

Being intrigued is one thing though; parting with my hard-earned cash was quite another. But how else was I going to find out? It was at this juncture that a compromise was reached; if I could get a lightly used Savannah for a good price, I could satisfy my curiosity and allow me to complete my survey of the full gamut of what Barr & Stroud were offering to the budget conscious consumer. An opportunity soon arose when my interest was piqued by an advert posted on the dreaded ‘fleabay’. The seller posted some high quality images of a 8 x 42 Savannah, indicating that it was used only a few times and that she had misplaced the little cap that covered the thread allowing the instrument to be mounted on a monopod or tripod. She was offering £80 for the unit plus £6 shipping. That represented a 50 per cent saving on the new price, so I bit the bullet and pulled the trigger on a sale.

As I explained in a previous blog, I was cautious about going for a binocular that offered an overly generous field of view, but when I read the reviews I noticed that no one was complaining about off-axis distortions in the Savannah, which sported a relatively huge perspective; 143 metres at 1000m, or an angular field of view 8.2 degrees wide! Afterall, this was a full degree wider than that offered by the 8 x 42 Sierra. Man, that’s a wide field, wider in fact than the vast majority of views offered even by premium manufacturers! For example, one of the widest models, the Zeiss Victory SF 8 x 42 offers a field of 148m at 1000m, so not far off the Savannah!

A few days after I made the purchase, the package arrived safely at my home. The owner had carefully packed it for transport up from England to bonnie Scotland. Inspecting the unit, I was relieved to see that all was well; I got the original hard case, the Savannah binocular with the ocular cups and strap attached, a lens cleaning cloth, the one-page generic instruction sheet, and of course, that valuable 10 year warranty. Cool.

The Barr & Stroud Savannah 8 x 42 roof prism binocular complete with stylish hard case, 10 year warranty card and single page instruction sheet.

I was quickly able to replace the missing B&S cap with the one borrowed from my 10 x 50 Sierra, which was now permanently affixed to the monopod adapter previously described in this link. So now, I had the complete binocular, cap an’ all.

Both the ocular lenses and the objectives looked pristine, with no defects that I could see.

Looking down at the ocular lenses. Note the specifications.

The pristine 42mm aperture objectives on the Savannah. Note the replaced B&S cap. Rubber objective lens caps come as standard with all the Barr & Stroud binoculars and fit  snugly and firmly in place so they won’t get dropped or lost easily.

The Savannah 8 x 42 has a number of different mechanical features in comparison to the Sierra model, including a slighlty larger focus wheel and a re-designed diopter adjustment mechanism situated immediately ahead of it. The binocular is a little heavier than the Sierra though, which I counted as a disadvantage, but that said, it is very solidly built with excellent fit and feel, courtesy of its tough, rubberised overcoat. I was surprised to learn though that even with its increased weight, it was about the same weight as many of the premium models on the market offering the same or similar specifications.Like the other Barr & Stroud models, the Savannah is weather proof, purged internally with dry nitrogen gas and O-ring sealed.

The twist-up ocular caps are slightly different on this model also, being slightly flatter and, dare I say, look a bit more elegant than on the Sierra and Sahara models. The Savannah offers the same generous eye relief to the user; 18mm, so are ideal for both eye glass wearers and those who prefer to observe without glasses.

The eyecups twist up securely in two clicks for use without eye glasses.

 

Like the Sierra, the Savannah 8 x 42 has an excellent close focus distance of just two metres. The diopter setting is not quite as rigid as the Sierra model though, requiring frequent checking to ensure that it remains in the desired position for optimal binocular performance. The Savannah is also fully multi-coated and the prisms are appropriately phase coated for the highest possible light transmission.

The Savannah comes with a much higher quality and more comfortable carrying strap, featuring the Barr & Stroud logo, which is a definite improvement over the basic strap accompanying the other models tested. This will be very much appreciated by those who use the instrument during prolonged field use.

A better padded carrying strap with the B&S logo comes standard with the Savannah range making their transport in the field more comfortable.

Optical Testing

Although the precise diopter adjustment can be closely approximated in daylight targets, I have learned to tweak it by focusing on stars at night. Specifically, what I’ve found is that the diopter position acheived during routine observations in the daytime are, more often than not, very slightly out when observing point sources like bright stars at night. This can be seen by a slight spiking of the starlight at best focus, which can thereafter be eliminated by making minute adjustments to the diopter dial. I would recommend this technique to others to get the best possible views out of their binoculars.

Focusing is very precise and intuitive and produces exquitely sharp images that display the objects in their vivid colours accurately and in very high contrast. In my research of some of the premium models, I discovered that in their quest to attain the highest levels of light transmission (95 per cent in this case), many experienced observers reported that the colour tone turned out to be a bit on the dull, or ‘cold’ side. Remarkably, the manufacturers opted to slightly reduce light transmission by a few per cent in order to generate more natural colour tones in their newer models. The Savannah suffers little from these problems however as the colour tones appear very natural and fully in keeping with a high quality field binocular. For more on this interesting development see this link.

Chromatic correction is excellent; you’ll only see it if you look very hard for it around high contrast objects when set against a bright overcast sky. No need for ED elements in a glass of this specification; an expedient luxury that adds practically nothing to the viewing experience. Of course, there will always be those who insist on having this feature; good luck with that!

The main reason I took a chance on the Savannah 8 x 42 is its prodigious field of view. Expecting to be a little underwhelmed, I was very pleasantly surprised to discover that the images remain very sharp across the vast majority of the field with only slight softening observed at the extreme edge. The same was true when I tested them out on bright star fields. The stellar images remained acceptably sharp over a field considerably larger than the 8x 42 Sierra, with negligible distortion at the extreme edge of the field. What absolutely blew me away though was an experience I had during the first week in December 2018, when I turned the Savannah 8 x 42 on the constellation of Orion which had now culminated in the south in the wee small hours. I was able to image the entire Sword Handle and the three bright belt stars of the Celestial Hunter with some room to spare! Both contrast and sharpness were very impressive and arguably one of the most immersive views I have ever enjoyed in any binocular! Internal reflections and flaring are also very well controlled.

The price one has to pay for this 25 per cent increase in field area over the Sierra model is increased mass; 819g as opposed to just 650g in the latter. Was the tradeoff worth it? I would have to say yes! The enormous, well-corrected field is quite simply awesome and worth experiencing despite the greater weight. I guess to create this brilliant wide field, one has to re-think the optics of this design and that necessitated adding different (or just more?) ocular lenses to the instrument.

Spiffing good.

So I wound up with two 8 x 42s. Now, as I’m no collector and don’t believe in hoarding stuff, I decided to gift the Sierra to a friend. I now have my ideal multi-purpose binocular and would unhesitatingly recommend it to anyone looking for a great, no-nonsense instrument at a very decent price (even new!).

Postscriptum: Check out what this youtuber had to say about the Barr & Stroud 8 x 42 Savannah binocular.

Full specifications of the instrument here.

 

Neil English is the author of Chronicling the Golden Age of Astronomy.

 

De Fideli.

 

 

Product Review: The Barr & Stroud Sierra 10×50 Roof Prism Binocular.

The Barr & Stroud Sierra 10 x 50 binocular with peripheral eyeshields.

 

There has never been a better time for the binocular enthusiast. Nowadays, a huge range of models are available that offer high quality optics for nature studies, birding and astronomy. Doubtless, this revolution is wrought by advances in technology; better glass, better coatings,  as well as steady progress in materials science. Greater competition among the various optics houses also helps drive prices down, so that many more people can take advantage of this new technological wave; and that is good news for a multitude of hobbyists.

I recently described my very favourable impressions of a new instrument; the Barr & Stroud Sierra 8 x 42 roof prism binocular, which offers excellent optics, good weather proofing, great compactness and very light weight compared with my old, well-worn 7 x 50 porro-prism binocular, which had served me well for three decades. The 8 x 42 is an ideal instrument for daytime applications, where its decent light gathering power and efficient transmission of light to the eye, yields images that have great colour fidelity and excellent contrast. As I also explained, the 8 x 42 can be used productively for night-time applications, where it offers good performance within the remit of its aperture.

Still, as good as the 8 x 42 is, I felt I was missing out a little were I to use the instrument for specialised deep sky viewing, compared with slightly larger instruments that have long been the staple of the binocular astronomy enthusiast; I wanted to be able to do binocular astronomy using only a binocular; under its own terms.

Enter the venerable  10 x 50. And that prompted me to seek out a high quality instrument that I could almost exclusively dedicate to night sky use. A good 10 x 50 would gain about about a half a visual magnitude over the 8 x 42 and its slightly higher magnification would be advantageous for pulling out faint deep sky objects that are not so well seen with the smaller binocular.  I had heard some great things about the Nikon Aculon 10 x 50 porro prism binocular and I seriously thought about acquiring it, since it seemed to offer a lot of bang for the buck, but when I considered its weight- 898g, it seemed rather on the heavy side. You see for me, weight is a brute fact: the heavier the binocular, the less I would likely use it.

Deeply impressed by the way the compact 8 x 42 handled various situations, I looked again for a roof prism model offering 10 x 50 specifications and it wasn’t long before my interest was piqued by the Barr & Stroud Sierra 10 x 50 roof prism binocular, which I felt was very reasonably priced. So I took the plunge and ordered one up.

Just like the 8 x 42, the 10 x 50 Sierra arrived very well packaged in an attractive box. The same soft, black carry case housed the binocular, as well as receiving the neat 10-year warranty card and single page instruction sheet.

The 10 x50 Sierra binocular in its soft carry case.

 

The binocular is very well built, with a strong, rigid bridge that is not easily moved once the proper interpupillary distance was set. Ditto for the diopter setting, which is quite stiff and thus not likely to budge in field use. Like the 8 x 42, the unit is o-ring sealed and purged with dry nitrogen gas making it fog and weatherproof (water resistant up to 1.5m for three minutes), Its weight is considerably lower than the Aculon; just 780g. The focuser is smooth and firm to the touch and offers an excellent close focus distance of just 2.5 metres (tested). It also has rubberised caps to protect both the objective lenses and the eyepieces. What’s more, they can be permanently affixed to the binocular so they won’t get lost in a hurry.

The 10 x 50 Sierra is fully multi-coated and the prisms are phase coated for optimum field performance.

 

Like the  8 x 42 Sierra, the 10 x 50 unit features fully multi-coated optics and the BaK-4 roof prisms are phase coated to maximise image brightness, contrast and colour fidelity.

Very nicely designed oculars ensure comfortable viewing, either with or without eye glasses. Note; the oculars are shown fitted with eyeshield peripheral shades (purchased separately).

The eyecups can be twisted upwards for use without eyeglasses, or can be kept fully down if oe decides to use them with eyeglasses.

Eye relief is very generous 17.8mm and the field of view offered is just under 6 angular degrees.

Full details of the 10 x 50 Sierra can be viewed here.

The very same afternoon the 10 x 50 Sierra arrived, I took off on my long country walk to see how they performed during daylight hours. The first thing I noticed was their additional weight; fully 130g heavier than the 8 x 42 Sierra. After a few miles of walking with the instrument hanging around my neck, I experienced significantly greater back strain than I was accustomed to carrying the lighter 8 x 42. This was fully expected however and affirmed my conviction that 8 x 42 would better serve me during daylight hours.

I fully expected a little more chromatic aberration, given the specifications of the 10 x 50 and this was confirmed by focusing on a distant hilltop against a bright overcast sky. Still, it was very minimal and perfectly acceptable. Certainly, it would never be enough for me to consider a model with ED glass; that would be overkill to say the least! The images served up by the 10 x 50 were beautiful, crisp and bright, with great colour fidelity and excellent contrast, although it was immediately acknowledged that I would be sacrificing some field of view over the 8 x 42.

While using the 8 x 42 for prolonged periods during my daily walks, I noticed that on bright days, light entering my peripheral vision was causing some annoying glare to seep in. This had nothing to do with the type or make of binocular but merely reflected an operational issue while using any binocular. Thankfully, I found a great solution; enter Eyeshields produced by a US-based company called Field Optics Research.

A good product for any binocular user. Eyeshields by Field Optics Research.

 

Costing £25 delivered, I received two pairs (one for the 8 x 42 and the other for the 10 x 50) of eyeshields which fit snugly onto the oculars and can be deployed at a moment’s notice. They remain permanently affixed to the eyepieces and fold down when not in use. Another neat feature of the EyeShields is that you can still use the rubberised dust caps with them on. They do a simple job, shileding your peripheral vision from stray light, but also stop wind-driven dust from accumulating on the oculars. They work really well, effectively eliminating the said glare I was encountering during my observations. Though a bit costly for what they really are- rubber eyeshields in a tin box lol –  I can certainly vouch for their effectiveness and would highly recommend them to any binocular enthusiast.

One thing caught my attention though: I noticed that the company state that the product is “patent pending”. I don’t know if something like this can really be patented though. I mean, I have similar eyeshields which came with some of my older orthoscopic and Plossl eyepieces, so it’s hardly something truly novel.

The eyeshields very effectively block peripheral light entering the eye while using binoculars in bright ambient light settings.

Ad Astra

Though I acquired the binocular at the start of November 2018, I was not able to conduct star tests until the evening of November 7, owing to a prolonged bout of cloudy, damp and misty weather, typical for this time of year, which all but extinguished the light from the stars. Seeing some breaks in the clouds after dark stoked deep feelings of joy, and I immediately grabbed the 10 x 50 to begin my observations. My first impressions were very favourable. This cost-effective instrument served up beautiful views of the Pleaides, my first target in northern Taurus. I immediately appreciated the wonderful contrast of the instrument and could instantly make out many more fainter members than I could see with the 8 x 42. The increased image scale was quite significant too, framing the asterism very well in the field of view.

Two tests of the size of the field were conducted; first with the Hyades, which was quite simply stunning in the 10 x 50 and I was delighted to see that the main ‘V’ shaped configuration was nicely framed in the binocular field with a little room to spare. The field came alive with many sparkling jewels, brighter and more numerous than in the 8 x 42. Star colours seemed even more vivid too.  Since the main part of the Hyades is in excess of 5 angular degrees wide, this comported well with the field quoted in the specifications table.

In the second test, I was able to get brilliant white Rigel just inside the same field as the Orion Nebula (M42), a distance I estimated to be about 5.7 angular degrees, so quite close to what the manufacturer claimed. It’s nice when the stated specifications agree with experience!

At tightest focus, brilliant yellow Capella in Auriga showed no fringing of any sort that my average eyes could detect, and moving the brilliant autumn luminary to the edge of the field showed that it remained agreeably sharp and tight; perhaps even a tad better than the wider field offered up by the smaller 8 x 42. I reasoned that this was not to be unexpected, as it is easier to get a better corrected field as the field shrinks in size.

Sweeping the binocular through the heart of Auriga showed its clear superiority over the 8 x 42. The 3 Messier open clusters were easier to pull out from the background sky and I was also able to more easily see a number of other fainter nebulae that were mere suggestions in the smaller Sierra binocular.

As a resolution test, I steadied the binocular on the side wall of my house and aimed it at golden Albireo, now rather low in the northwestern sky. I believe I was just able to pick off its companion, something I have not been able to achieve using the 8 x 42 after several attempts.

The weight difference between the Sierra binoculars is immediately obvious under the painted canopy of the night sky. It is harder to hold the 10 x 50 steady, but I find that this is less important for large deep sky objects than it is for studying smaller targets like individual stars, where the wondrous creation of the human eye-brain seems to act as a natural image stabiliser. I found it beneficial to move my hands further forward in order to get a better grip of the objective end of the instrument while in field use. This strategy definitely helps me to get the most stable images from the 10 x 50 during prolonged (greater than 20 seconds or so) observations.

In another test, I compared the binocular views of M 35 in Gemini, which had cliimbed out of the eastern murk, reaching a decent height just after local midnight. While both binoculars easily showed the large, roughly wedge-shaped open cluster, its sub-optimal altitude enabled only a few stellar members to be made out in the 8 x 42 but many more were discernible with the larger 10 x 50.

Some other daylight tests:

Many inexpensive binoculars often come with misaligned prisms which cut off some of the light reaching the eye. This is especially true when the product comes via courier. I’ve had a large 15 x 70 binocular in the past that came badly misaligned, which made me far more cautious about buying a binocular online. Thankfully, this was not the case with the Barr & Stroud binoculars, which were all properly and securely collimated in the factory prior to dispatch.

A simple way to test this is to examine the shape of the exit pupil of the binocular when pointed at a bright light source. A square or non circular shaped light shaft is an easy way to show if the prisms are undersized (thus losing some light) or misaligned. As the photo below shows, the exit pupils of the 10 x 50 are round, as are the 8 x 42s,  indicating that all is well.

No sign of a squared off exit pupil on the Barr & Stroud binocular.

 

Like the 8 x 42 previously tested, the 10 x 50 showed little sign of pincushion distortion while examining the profile of a horizontal roof located about 100 yards distant.

Attaining binocular stability without sacrificing mobility

As I stated previously, binocular astronomy, for me, generally means hand-held viewing, without the need for tripods or other more elaborate kinds of mounts that just get in the way. That’s one of the reasons why I eventually grew disillusioned with large and heavy binoculars. But any 10 x 50 unit, whether roof- or porro prism-based, will eventually show its limitations in regard to attaining rock steady views of star fields, or for teasing apart tighter binocular double stars, or even for seeing the most detail on the Moon. One way round the problem is to stabilise the binocular on a fence or a wall, but this convenience is not always practicle, especially if you’re on the move. The best compromise is to use a lightweight monopod and it is to this device that I turned to in field testing.

One thing the reader must be made aware of is that roof prism binoculars will not, in general, be compatible with standard porro prism binocular tripod adapters. Many of these adapters might fit the roof prism binocular but the stalk will more often than not be too wide to attain the optimum interpupillary distance so important for the most comfortable, immersive views. To that end, I ordered up a smaller adapter especially designed for medium sized (up to 50mm aperture) roof prism binoculars. I elected to go for a well machined, high-quality unit marketed by Opticron (shown below).

The Opticron tripod adapter designed for medium sized roof prism binoculars.

Having acquired a monopod some time ago for use in landscape photography, I was eager to see how the binocular would fare using this configuration, so I began a set of field tests using this device to see if it would tick all the boxes.

The Opticron adapter mates to the 10 x 50 Sierra very well, enabling the correct interpupillary distance to be maintained.

A good fitting: the Opictron tripod adapter mates to the binocular perfectly and will allow the user to re-adjust the interpupillary distance for optimum field performance.

 

The binocular with its adapter readily screws into the monopod. The whole configuration is still very lightweight, ultraportable and is now ready for testing under the night sky.

The 10 x 50 Sierra securely mounted on the lightweight monopod.

To what degree will the monopod stabilise the images in the 10 x 50? Off the bat, it will yield images that are more stable than an image-stabilised (IS) binocular, without the attending arm strain, high cost and need for battery power, but will fall short of that generated by a tripod.

Shortly before local midnight on the evening of November 15 2018, I stuck my head out my back door to discover that the sky had cleared somewhat after a rainy spell. The air was grand and mild, and the Moon had set shortly after 11pm, yielding a fine, dark sky. Pleasantly surprised, I ran in and fetched the 10 x 50 atop the monopod. The Pleiades was very high up in the south; ideally placed for binocular viewing. Settling into my recliner, I was able to negotiate a very comfortable position with the monopod securely held against the ground. Centring the asterism in the field of view, I was dumb struck by how good the view was; a blizzard of blue white stars piercing through the canopy of night in a blaze of glory! The effect of stabilising the view makes an enormous difference to what you see. Some highly experienced binocular users claim that you can go up to a magnitude fainter if the image is stabilised. I don’t know whether that’s accurate or not, but what I can say is that it was a supremely joyful experience. I just lay there for twenty minutes in the dark feasting my eyes on the celestial apparition before me. During the spell, cloud patches of varying thickness marched across the sky, diminishing the brilliance of the Pleiads by varying degrees, but as they passed through the full splendour of the cluster reasserted itself.

I will add a strong ball & socket adapter to the monopod so that I can make angular adjustments to the binocular. That way, I will increase the viewing comfort that little bit more.

That was my first experience with the monopod; a first step. In time, I’ll take another.

November 17 2018:

After rummaging around in me ole box of tricks, I selected a good ball & socket adapter for the 10 x 50 binocular. Although I had a few of these handy, I elected to use one that could carry the 780g instrument with ease. My best one, shown below, can carry cameras and other equipment up to 2 kilos in weight.

An all-metal ball & socket adapter mated to the monopod with a 2 kilo carrying capacity.

 

It worked really well with the binocular in daylight tests. Indeed, it will give me yet another degree of freedom whilst conducting my observations of the night sky.

Another view of the ball & socket adapter mounted on the monopod.

 

So, there it is; I think I’m ready for another session under the stars. What attracts me to this arrangement is its sheer simplicity; increased stability, easy to carry, easy to manoeuvre, easy to store away!

Simplicity itself.

Round about 6pm local time, I ventured out to see if the clear spells we enjoyed during the afternoon had persisted. I was in luck. The 10 day old gibbous Moon was low in the southeast, still a couple of hours before meridian transit. Eagerly, I turned the 10 x 50 astride the monocular mount at it, focused, and then carefully assessed the image.

I was very pleased! Our 70 per cent illuminated satellite showed some wonderful detail, easily superior to the smaller 8 x 42. The prominent ray crater, Copernicus, stood out a mile, as did Clavius and Tycho in the southern highlands. Eratosthenes, Plato and Archimedes proved easy too. The Apennine Mountains were clearly seen running from northeast to southwest and the various maria; Tranquillitatis, Fecunditatis, Serentatis, Nubium and Imbrium were all beautifully presented. Some faint stars in the vicinity of the Moon were easily seen in the 10 x 50. Thin, whispy clouds often ran across the lunar countenance, acting like a natural filter and increasing contrast. The upper edge of the Moon had a very thin bluish hue, whereas its southern counterpart was similarly tinged yellow. I attributed this in the main part to atmospheric refraction owing to its fairly low altitude (20 degrees) at the time the observation was made. Even at its brightest, glare was really well supressed, just like the 8 x 42 Sierra.

The Moon really comes alive in the image-stabilised 10 x 50!

The observations were conducted just standing up with the monopod, and I was able to tweak its pointing accuracy by making small adjustments to the ball & socket bearing. Turning over to the east, I aimed the binocular at Alpha Persei and made some more adjustments to the ball & socket so as to obtain the most comfortable standing observation of the binocular field. Even in bright moonlight, the rich starfields around it were wonderful and sharp almost all the way out to the edge, with excellent contrast.

Final testing: November 18-20 2018

Guid graith.

With unsettled weather being the rule rather than the exception over the last few days, my final tests were mainly conducted on a bright gibbous Moon, now rising much higher in the sky than previously reported on November 17. Whether seated, reclining or standing, the monopod is an excellent platform for image stabilised binocular astronomy, as it’s very easy to find a supremely comfortable position to conduct observations for all altitudes, from the horizon to the zenith. The lunar images remain sharp, with high contrast and very little in the way of glare evident to my eye. The extra image scale (25%) over the 8 x 42 is immediately appreciated, allowing lunar details to be more easily discerned at a glance. Some brief spells observing star fields in bright moonlight also produced very satisfying results. Suffice it to say that I cannot wait for the Moon to get out of the sky so that I can enjoy the wonders of the winter dark with this little instrument.

I have just one quibble with the 10 x 50; the soft carry case is identical to that which came with the 8 x 42. The case is ideal for the latter but is a little too small for the larger 10 x 50. Not a big deal but it should be said.

The Barr & Stroud 10 x 50 is the ideal astronomy binocular, offering exceptional perfromance at a price that meets most folks’ budgets. It’s solid construction, quality optics and very attractive price makes it an exceptional value in today’s market. Indeed, in an age where it is so very easy to get carried away by gimmicks and clever marketing ploys that pressurize individuals to depart with relatively large amounts of money, it is very reassuring to know that one can acquire this level of performance for a very reasonable financial outlay.

I heartily recommend these binoculars to stargazers everywhere and hope that they will give the reader as much joy as they have given me.

Thanks for reading.

 

Neil English is writing a new book dedicated to the ShortTube 80 achromatic telescope.

 

De Fideli.

Product Review: The Barr & Stroud 8 x 42 Sierra Roof Prism Binocular

The Barr & Stroud 8 x 42 roof prism binocular.

 

With some sage commentary from former Sky & Telescope columnist, Gary Seronik.

Binoculars are indispensable tools for the naturalist and amateur astronomer. Their strength lies in their ease of use, low-power, wide-field views of the Creation, whether terrestrial or celestial. In this era of high technology, there is a huge number of models to suit just about everyone’s needs, wants and budgets. Content with my old 7 x 50 porro prism binos for three decades, I came to realise recently that it would be good to get a newer model that was better suited to my life circumstances.

I had grown older you see, with the result that the maximum diameter of my pupil could no longer open to 7mm. I became less tolerant of the fairly substantial weight of the 7 x 50s too, especially when I took some time out to relax on a recliner in my garden to gaze upon the heavens for prolonged periods of time. The 7 x 50s also suffered some knocks over the years and once they were fully submerged when I accidently slipped on some moss and fell into Loch Lomond lol. Luckily, though a source of considerable hilarity to my travelling companions, the ordeal wasn’t the end of the world, and though the prisms became mis-aligned, I managed to get them repaired at reasonable cost.

But what really catalysed my desire for a new binocular was the recent acquisition of an inexpensive 10 x 50 binocular I received in a swap (barter) for an eyepiece with a fellow amateur. At first I was thrilled with the 10 x 50s. They had a suitable exit pupil (calculated by dividing the diameter of the objective by the  magnification), but they were quite heavy and owing to their ‘fully coated’ specifications, manifested significant light loss and reduced contrast owing to the presence of internal reflections when pointed at a bright light source.

I knew what I wanted going foward though. The binocular needed to be light weight but not feather-weight, as my experience with small compacts were somewhat less than inspiring. Somewhere between 600 and 700g would be ideal. The instrument had to be fully muti-coated to reduce light scattering inside to an absolute minimum. I could dispense with ED glass, as at the magnifications I intended to use the binocular at, I would be very hard pressed to see any secondary spectrum and I wasn’t going to splash out on an optical feature I could’t readily see! Much more important for me was that the binocular be well made and have a secure, rugged feel to them in field use.

I considered field of view too; at least 7 angular degrees but not overly wide since I reasoned that although some models were being offered with impressively wide fields up to 8 angular degrees or more, they would likely suffer more from off-axis aberrations that I would notice in field use.

Many of the ‘premium’ models also had features that I could readily do without as well: a slightly flatter field at the edge of the field, for example, or faster, smoother focusing that might be somewhat more important for observing fast moving wildlife at close hand; or a lockable diopter setting; those kinds of things.

Waterproofing would be a bonus, for sure, but not essential, as I don’t spend my days wading through swamps in search of feathered friends lol!

I decided that a full-size 8 x 42 roof prism binocular was the way to go. I was delighted to see that even very highly respected brands were offering many of the attributes I wanted without ED glass elements. For example, here’s one Fujinon model I considered. If Fujinon of Japan did not consider ED glass as an essential feature in a modern binocular, then why should I?

Consulting former Sky & Telescope columnist, Gary Seronik’s beautifully illustrated book, Binocular Highlights (Second Edition 2017), I was able to affirm what I felt about the view served up by a premium optic compared with mid-priced models:

….You can get good optics for relatively little money. So what do you get if you spend ten times as much? In terms of the actual view, not as much as you might expect. Yes, the more expensive binoculars have better optics that will deliver more light to your eyes and sharper images, but the difference is not night and day. What the extra money does buy is mechanical quality. Expensive binoculars can withstand the inevitable bumps and knocks of everyday use without trouble, and having focusing mechanisms that are sure and precise.

pp 11

 

Being new to this type of binocular, I did however find out the hard way that not all roof prism binos were created equal. My first purchase was a model that did have everything I was looking for, save for phase-coating technology which corrects for the inherent design flaw in all roof-prism binoculars. Finally, I purchased a model that did tick all my boxes; enter the Barr & Stroud Sierra 8 x 42.

It’s specifications can be viewed here.

The Sierra 8 x 42 came well packaged inside a handsome box. As well as the binocular, I received a lens cloth, neck strap, soft, padded carry case, a single-page instruction sheet and a warranty card (10 years).

Right from the get-go, I was very impressed with the fit and feel of the binocular. The fern-green body is fashioned from polycarbonate with a rubberised overcoat. The central bridge was set at just the right degree of stiffness, ensuring that when I adjusted the inter-pupillary distance, it was rigid enough to stay snugly in place; so no need for constant re-adjustment when taking them from their case. Both the objective and ocular lenses had good rubber-like caps that can be affixed to the binocular with a much reduced chance of getting lost while on the move.

The Barr & Stroud Sierra come with nicely made, stay-on rubber caps for both the ocular and objective lenses. Very handy both in the field and during storage.

 

Both the objective and ocular lenses have lovely anti-reflection coatings that make the lenses all but disappear when looking straight through them.

The great anti-reflection coatings on the achromatic objectives of the Barr & Stroud Sierra.

 

The Sierra come with adjustable eyecups that click up or down for use with or without  eye-glasses. With its generous 17.8mm eye relief, eye-glass wearers will be able to enjoy the full field of view by keeping the eyecups in the fully down position. I do not use eye-glasses when observing, so I always have the eyecups twisted fully upwards.

The twist-up eyecups ‘click’ into place for comfortable viewing of the entire field for use with or without eye-glasses.

 

The diopter setting is located under the right eyecup. It is satisfyingly stiff and, as a result, fairly difficult to adjust. I thought this was plenty good enough for my use, as it has not budged a millimetre since I made the adjustment for my own eyes on the day they were acquired!

The diopter ring is located under the right-hand eyecup and is very stiff and difficult to move out of position while in field use.

 

As the specifications reveal, the instrument is nitrogen purged and o-ringed sealed making it fog and water-proof. Since molecular nitrogen [consonant with the name ‘azote’, (meaning ‘without activity’) bestowed upon it by early chemists] is quite an inert gas, it also ensures no moisture- or oxygen-induced corrosion will occur to its internal components for the foreseeable future. Argon gas filling would have been better, of course, since it is even more inert (being a Noble element) than nitrogen and its larger atomic mass would ensure even more sluggish diffusion-based leakage over the years. But for my purposes though, ordinary nitrogen was deemed perfectly acceptable. The specs also say the instruments have been immersion tested and can withstand being submerged in up to 1.5 metres of water for 3 minutes; that’s plenty of time to retrieve them if ever an accident should occur!

I’ll not be testing that by the way, lol!

    Optical Testing & Handling in the Field

It does exactly what it says on the tin!

 

The Sierra 8 x 42 provide instant gratification from the moment you pick it up. It feels very secure in the hand. The view is very clear and sharp and colour rendition sensibly perfect. The factory collimation was spot on. The focus wheel is very responsive and smooth allowing you to zoom in on a subject as close as 6.5 feet all the way out to infinity. If you look carefully at the edges of the field, there is some softening of the image as well as a trace of chromatic aberration but not enough to distract the vast majority of users. Examining a horizontal roof at 30 yards distance revealed very little pincushion distortion.

Comparing it to my old 7 x 50s revealed something rather shocking; the image was actually brighter and sharper in the Sierra, despite it having smaller objective lenses ( 42mm as opposed to 50mm). I attribute this to solid advances in the application of better coatings to all optical components and superior baffling of stray light in the roof prism binocular. Focusing on the middle distance, the binocular provides very impressive depth of field perception but maybe not quite as good as that provided by their porro prism-based counterparts.

Definition of daytime targets is excellent. It presents autumn leaves in their beautiful colours and focusing in on tree trunks showed up its wonderful textured grain. I can easily carry them round my neck for many miles and with little in the way of neck strain. The binocular can also be attached to a tripod if need be using the 1/4-20 threaded socket found under the B&S logo at the front of the bridge. Just unscrew the plastic cover and screw in the tripod adapter.

As a rather severe test of how well stray light is managed in the binocular, I pointed it at the full Moon. The inexpensive 10 x 50s showed clear evidence of internal reflections producing annoying glare in the image and thereby reducing contrast. To my relief, the Sierra 8 x 42 showed very little in comparison indicating that stray light was being very well controlled.

A week after full Moon, I examined a rising last quarter Luna and again, the image was very impressive; there being very little glare and contrast remaining very high. The only false colour I could see was attributed to atmospheric refraction. The battered southern hemisphere with its vast crater fields stood out well, as did the contrast between the brighter and darker maria. I particularly enjoyed seeing the wonderful earthshine from the dark hemisphere of the Moon which made the view all the more magical.

Continuing my adventures with the Sierra under the stars, the binocular has a wide field of view (7.33 degrees), allowing you to take in generous swathes of sky. Stars focused down to tiny pinpoints across the vast majority of the field, with only the edges of the field showing a slight softening and the merest trace of lateral colour. I judged the contrast to be very good.

Confident that I had indeed obtained a very good binocular, I relaxed and just enjoyed the magnificent views it served up of large deep sky objects; the Hydaes was wonderful and filled the view with lots of room to spare, the Alpha Persei Association was spell-binding with many dozens of hot, white stars assaulting my eyes. The Pleiades was a beatufiful sight to behold. Bright stars such as Aldebaran, Capella and Vega faithfully revealed their true colours (orange, yellow and blue-white, respectively).Running the binocular through the Milky Way in Cygnus and Cassiopeia was a joyous experience and proved quite overwhelming to this tester.

The Sierra 8 x 42 will be an excellent new tool in my arsenal of optical instruments. It will complement the detailed, close-up views served up by my telescopes. The binocular will be accompanying us on our up-and-coming family vacation to the Solway Firth in southwest Scotland next week (commencing Monday October 15 2018) together with my 130mm f/5 Newtonian travel ‘scope.

The perfect binocular accompaniment.

 

I heartily recommend this binocular to amateur astronomers, nature watchers, for those who love poking around the landscape, or as the perfect optical accompaniment for a day at the races. It will offer up very satisfying performance at a price that won’t break the bank. It provides excellent value for money and, if properly cared for, provide a lifetime of wonderful views.

Postscriptum:

Please check out some other reviews of Barr & Stroud Binoculars:

The Barr & Stroud Sierra 10 x 42 Sierra

The Barr & Stroud 8 x 32 Sierra

The Barr & Stroud Savannah 8 x 42

 

Neil English’s new book, Chronicling the Golden Age of Astronomy, explores  four centuries of visual telescopic astronomy, as well as the pantheon of colourful characters who helped shape both the hobby and the science today.

 

De Fideli.

A Tale of Three Binoculars

My 30-year old 7 x 50 binocular.

 

It was just over 30 years ago when I was gifted a nice 7 x 50 binocular by my girlfriend. They featured a 7 degree field, multi-coated optics and BaK-4 porro prisms. They served me well all these years on holidays, walks and for casual stargazing. They weren’t cheap either. Lesser units would have fallen apart by now, but after trying a few modern binoculars out I knew that technology had moved on, mostly for the better.

And so had my eyes.

Now that I’m older, I wanted a binocular that had an exit pupil more suited to my age. I wanted an instrument that was more light weight, so that I could observe for longer without using tripods. I wanted a binocular that would do well in a variety of situations, from nature watching from dawn to dusk, and for astronomy. They had to be robust and ideally weatherproof to a degree. My ideal binocular views had to serve up sharp, colour pure views of autumn’s radiant hues but also allow me to throw caution to the wind and just enjoy the glories of the night sky from the comfort of a recliner. But which ones to buy?

Alas, I found that choosing a model that ticked all the boxes for me to be a daunting prospect! Today, we have so many makes to choose from; which is a good thing. My experience with telescopes came in very handy though. Not easily swayed by marketing gimmicks and wishy-washy hyperbole, I slowly pared them down to size.

I decided I wanted a fairly compact, full-size binocular that would offer good light grasp, so a clear aperture of 42mm would be about the minimum that would do the trick. I wanted a fully multi-coated instrument to maximise light transmission to the eye and reduce glare on bright objects to an acceptable minimum. They had to be well made with a decent warranty should they get damaged or worn out from regular use. And they had to present good value for my hard-earned cash.

I narrowed my search down to a good roof-prism binocular as these had many of the features I was looking for; small, light weight, decent light grasp, ultraportable etc. Two magnifications were considered, 8x or 10x. With 10x you’d get a smaller exit pupil and lose some advantages of using them in low light conditions. 10x would also introduce more shake and would be more difficult to accurately focus while in use too, so I decided on 8x; an 8 x 42 binocular.

I went to amazon.co.uk to check out the user reviews of a variety of models I had an interest in. In many ways, these types of reviews give the prospective buyer a more rounded view of what it’s like to use a given model, as they are often more honest and less biased than those offered by so-called ‘experts,’ who, more often than not, succumb to clever marketing ploys and had a tendency to push premium products over more economical models that might still offer perfectly acceptable performance. I found that birders, for example, often highlighted a variety of mechanical and optical features that were largerly superfluous to my needs. I didn’t really need super-fast focusing, locked in dioptre settings, nor ED elements in the objectives. At such low powers, one would be hard pressed to see the advantages of employing low dispersion glass and most of the online literature seemed to over-emphasise their advantages even though I knew that it would only make a small (insignificant?) difference to the views. Afterall, how many amateur astronomers insist on having ED finder ‘scopes eh? Why haven’t 8 x 50 ED finders or some such become the industry standard, if they really offered any tangible advantage over good ole crown & flint? The honest answer is that they’re unnecessary, and so can be dispensed with.

As a case in point, check out this user review of the Vortex 10 x 42 Diamondback roof prism binocular. The gentleman states that he was asked to try out the more expensive Viper model with ED objective elements in a blind test. He states that he couldn’t really tell the difference in field use. I have no reason to doubt the gentleman’s conviction. Why lie on such a trivial matter?

No, a good, no-frills, traditional achromatic binocular to match my average eyes was what I was shopping for!

I went with a company that had a long track record of producing high quality optics, as I reasoned that such knowledge would be invaluable in the construction of a well-made binocular. Many companies selling such binoculars were not long in the game though, so my instinct was to avoid them. I gravitated toward an old British firm that had produced optics for the military in two world wars; Barr & Stroud.

Now bought out by OVL, Barr & Stroud  re-entered the sports optics market by bringing out a range of affordable roof prism binoculars in an 8 x 42 format and my first purchase was the Sahara 8 x 42, which retails for about £70-£90 UK.

The Barr & Stroud Sahara 8 x 42.

 

Though under no illusions that these are British made, Barr & Stroud binoculars are now assembled in China, just like those marketed by Vortex (a US-based company) and many other companies. They are supplied with a nice, soft carry case, neck straps, a lens cleaning cloth and have a 10-year warranty.

The Sahara 8 x 42 binocular comes in attractive box with a good carrying case with the usual accessories.

 

The specifications of the Sahara 8 x 42 model can be viewed here.

The Sahara is a joy to use. It’s small and light weight (670g), has good eye relief (17.5 mm) and with its twist up eyecups, will allow those who must wear eye glasses (I don’t) to enjoy the expansive field of view (7.33 angular degrees). Images are bright and sharp and colour fidelity is sound. With its fully multi-coated optics, contrast and glare suppression are excellent too in comparison to my old 7 x 50s. You really have to look for chromatic aberration but it is there. You can best see it by focusing on the edge of a telephone pole against a bright, overcast sky background, but is minimal and not in the least bit intrusive(I’d say mostly bum-fluff). At the edge of the field, the image gets a little softer with some slight fringing during daylight hours but it will never be enough to disturb the vast majority of users. Focusing is smooth and intuitive, not overly stiff or loose and it has an excellent close focus distance of just under 2m (measured) to allow you to enjoy insects, flowers etc at close range. It also has adequate waterproofing for my intended uses for it.

Night time views were very impressive too. Stars are sharp and pinpoint across the majority of the field. Only by using a stable tripod, will you be able to notice a little defocus of the stellar images at the edge of the field. All in, I would rate the Sahara as very good and considering its modest cost; a great bargain in today’s market! These guys certainly know how to make a good binocular!

Shortly after purchasing the Saharas, I began researching the properties of roof prisms and discovered that they have a significant design flaw. In the roof prism design, the two halves of the collected light from the objectives travel through the prism independently and are recombined before reaching the eyepieces. Because the path of the two wave trains are of slightly different lengths, one half of the light takes a little longer to travel through the prism than the other. When the two halves of the image are recombined, the wave with the longer light path will be slightly out of phase with the light that undergoes the shorter route. This results in a combination of destructive and constructive interference of the wave trains, affecting the colour balance, contrast and fidelity of the binocular image.

Note that this flaw does not affect porro-prism-based binoculars!

By introducing a special phase coating to the prism undergoing the shorter light path, optical designers can slightly retard the wave train, thereby correcting the phase difference with the other wave train. This results in sharper, brighter images with higher contrast; in theory. As I researched this some more, I discovered that the result was quantitatively significant; 8 per cent according to the manufacturers. Intrigued, I looked for a Barr & Stroud model that had this phase coating as the Sahara’s did not have this technology built in and that quickly led me to their 8 x 42 Sierra model.

The Barr & Stroud 8 x 42 Sierra binocular.

 

Luckily, the Sierra was only a little bit more expensive than the Sahara. Full specs here.

Otherwise sharing very similar specifications to the Sahara, the Sierra 8 x 42 is also slightly lighter (650g), coming with the same soft carry case and accessories as the former. The polycarbonate body was also a little different in the Sierra compared with the Sahara, as the above images show. When it arrived, the first thing I did was undergo a test to see if there was any significant difference between the images. Examining a brightly lit scene with a trunk of a tree shadowed by some over-hanging branches and comparing the two binocular images, I must admit that the Sierra was that little bit better. It’s difficult to describe in words but I suppose I’d say that the Sierra image had a little bit more ‘zing’ to it. The image was that little bit brighter and the colours more vivid. Contrast was also better by a shade.

Based on this test, I think phase coating technology is definitely worth having. Subsequent research of other high-end and mid-priced binoculars revealed that they all possessed these phase coatings. I see them as increasing the overall efficiency of light transmission, improving the image in a way that the human eye would notice in a critical test.

In another test comparing my 7 x 50s to the Sierra’s, I had to immediately concede that the images in the latter were far superior to the old porro prism binocular. The image was actually brighter even though it only had 42mm objectives(as opposed to 50mm in the auld yin) and the contrast far superior. The Sierra also presented a larger field of view.

Man and his technology!

Before describing my experiences with the Sierra 8 x 42 in any more detail, I was curious to see how the unit would fare compared with a high-end binocular with roughly the same specifications. As luck would have it, my coalman is a keen birder and dabbles in hunting big game. He’s the proud possessor of a Swarovksi EL 8.5 x 42 binocular, which retails for about £1800 UK. When he came to deliver some coal I got chatting with him and asked him if he would be so kind as to bring them by some afternoon so that we could compare and contrast the images garnered by these binoculars. He agreed.

The Swarovski EL 8.5 x 42 roof prism binocular.

 

Though certainly not a ‘gayponaut’ (a word of my own coining, fomally defined as: an irrational obsession with small ED optics), my coalman, Graham, bought his Swarovski’s about ten years ago, and I was glad to see that they looked as though they’d been used. When I asked him why he chose them he said, “they’re supposed to give brighter views in low light.”  I thought that answer was a little vague though. He didn’t seem to know anything about the fluorite element in the objectives, or the effects of coatings on the optics. He was simply won over by the advertising. I believe this is common among buyers of high-end optics. Afterall, you don’t need to know anything about an internal combustion engine in order to drive a car do you?

Indeed, I knew far more about his Swarovski’s than he did. Nevertheless, we compared the images. I got a shot of Graham’s 8.5 x 42s and he got a chance to test out my 8 x 42 Sierra’s. The results were interesting.

I felt the image quality was excellent in the Swarovski’s. It gave a slightly more neutral colour tone to the Sierra’s in a very slightly larger true field (7.6 angular degrees). Contrast was excellent with really first-rate definition. The built-in field flattening lenses in the eyepieces improved the edge of field correction, and the slight colour fringing I had tried hard to detect in my Sierras was invisible in the Swarovski’s.

Graham liked the Sierras too though. Indeed, he said to me that, ” they’re pretty much the same aren’t they?”

I found it hard not to disagree. I felt the images were much more similar than different.

But what I did appreciate were the mechanical attributes of Graham’s binocular. Its buttery smooth focusing wheel made it easy to adjust focus distance from about 4.5 feet to infinity very swiftly; a bonus for birders I guess. I also appreciated the wonderful diopter adjustment apparatus and hearing the ‘click’ as it was turned to the correct setting.  This clever diopter locking mechanism means that there’s little chance of it slipping out of place during field use. Great, but not something I couldn’t live without.

The Swarovski’s body is a very rugged magnesium alloy chassis which gives a feeling of reassurance while handling the optic, but I didn’t really understand how it would be more resistant to corrosion over the far less expensive polycarbonate body usually found on the majority of sports optics. What Graham and I did notice was the significant weight difference between the models. The Swarovski’s were nearly 200g heavier than the Sierra’s, something that would definitely have a bearing on observing comfort during prolonged field use.

The excellent life-time warranty on the Swarovski’s was something Graham appreciated. He told me that one of the caps on the ocular lens had worn out (they can actually be removed for easy cleaning of the eye lenses) but one of the company reps immediately fitted his unit with a new one; that’s great service!

In the end, I was very grateful to Graham for bringing by his high-end binocular. I was delighted to know that there wasn’t much in it optically. But then again, I kind of expected as much! Did the experience tempt me to save and invest in a Swarovski? I’d have to say no. My Sierra’s were plenty good enough, warts and all!

What to do with the Sahara’s? My sister- and brother-in-law love the great outdoors; camping, glamping, fly fishing, hill walking and sight seeing. The’ve never owned a decent binocular so these will serve as a suitable Christmas gift for them. I just know they’ll love it and use it!

As for the Barr & Stroud Sierra binocular, I will present a separate, in depth review of this instrument in another blog.

Thanks for reading!

 

Neil English is author of several books on amateur astronomy.

 

De Fideli.