A Work Commenced February 11 2025

Product: Oberwerk ED Ultra 15 x 56

Country of Manufacture: China

Clear Aperture: 56mm(measured)

Exit Pupil: 3.73mm

Field of View: 88m@1000m(4.7 angular degrees)

Close Focus: 15m advertised, 17.4m measured

Focuser Configuration: Individual Focus(IF)

Coatings: Fully Broadband Multicoated

ED glass: Yes(FK-61)

Field Flatteners: Yes

Prism Type: BaK

Waterproof: Yes

Nitrogen Purged: Yes

Weight: 1.48 kilos

Accessories: Padded soft case, mounting bracket, rain guard, objective caps, neoprene neck strap, microfibre lens cloth, test & warranty certificate.

Warranty: 5 Years

Price(UK) £549.95

When it comes to large, high-power binoculars, Oberwerk is a name that trips off the tongue. For a quarter of a century, its founder, Kevin Busarow, has been servicing the astronomical community with a swathe of innovative products that deliver excellent value for money. One of the most admirable attributes of Oberwerk is their commitment to developing their optical wares as new technologies become available. 

The original Oberwerk Ultra models had good achromatic optics, full sized prisms and housed in a robust, weatherproof chassis. Fast forward a decade and the same series now possesses extra-low dispersion objectives and field-flattening optics with significantly improved eye relief for eyeglass wearers. 

Another point of significance is Oberwerk’s commitment to the Porro I prism design, which has several advantages over larger aperture roof prism models. For one thing, because the eyepieces of roof models are aligned with their objectives, their minimum IPD becomes progressively larger as the aperture exceeds 50mm. A 70mm roof would probably have an IPD near 70mm meaning that many users, yours truly included, could not bring the barrels close enough together to merge the images. That’s not an issue for Porro I  prism designs, the objectives of which have large offsets to allow the majority of human faces to engage with them.

In addition, larger roof prism binoculars of high optical quality are more expensive than a well executed Porro I model of equal quality. 

Having tested hundreds of binocular models – both roof and Porro – particularly under the stars- I have cultivated a strong preference for Porro prism models in larger apertures. Stars present as tinier pinpoints without the commonly seen diffraction spikes all too often witnessed in many roof prism models. 

So when Oberwerk launched their new ED Ultra Series of Porro I system binoculars, I became particularly intrigued by one model: the 15 x 56, for reasons I shall elaborate on later. What follows is a detailed review of this instrument, based on a couple of months of experience during daylight hours, but also after dark.

A Closer Look at the Oberwerk ED Ultra 15 x 56

The Oberwerk ED Ultra is an exceptionally handsome and beefy binocular, tipping the scales at 1.48kg. The tough magnesium alloy chassis is overlaid by an attractive grey textured rubber armouring, with black and red accents placed at the sides of the barrels. 

The eyepieces are focused individually and are clearly marked with their  +\- 5 dioptre compensations. They rotate smoothly and accurately, maintaining their positions well. The eyecups are fashioned from black rubber and have plenty of useable eye relief. Folded down, I was able to easily engage with the entire field using spectacles. Indeed I later found that while I do not use eyeglasses while looking through binoculars, I strongly preferred using the 15 x 56 with the eyecups folded down, as shown below:

While it is certainly true that Porro prism binoculars are more prone to being whacked out of alignment, these new Ultra ED models possess a 3-point floating plate housing for the full-size BaK 4 prisms at the heart of the instruments. That’s very reassuring, as this will almost certainly mean these models will hold precise collimation indefinitely.

Both the objective and eyepiece lenses exude attractive pink coloured anti-reflection coatings, very similar in fact to their excellent SE series instruments.  

Another neat feature of the 15 x 56 ED Ultra is the easy to read interpupillary distance measure on the bridge which is of great assistance in maintaining the optimal spacing of the eyepieces with one’s eyes.

The central hinge is fashioned from strong metal, rendering adjustments very smooth and precise. Once set, it’s sufficiently rigid to hold its position precisely.

Mounting Options:
The interesting thing about a 15 x 56 configuration is that it’s neither lightweight or overly heavy. That means it can be enjoyed handheld or mounted. I used a simple, Rick Young harness to transport the instrument while exploring the rural landscape near my home. A binocular harness distributes the weight of the binoculars more evenly across your body, reducing strain on your arms and hands. This allows for a more stable hold, especially during prolonged use. 

In addition, there’s less chance for hand tremors or involuntary movements to affect what you’re viewing. This is particularly beneficial for observing distant or moving objects. What’s more, using a harness can encourage better posture, as it allows the user to maintain a more relaxed position while viewing. Proper posture can also help in reducing fatigue, which in turn helps maintain steady vision. All in all, these ergonomic features collectively help stabilise viewing through the Oberwerk ED Ultra 15 x 56. 

Another option is to mount the binocular on a sturdy photographic tripod via the supplied bracket. While this is a good way to obtain steady views for terrestrial viewing, I found it rather inconvenient for astronomical observing, preferring instead a sturdy monopod. I elected to use Oberwerk’s excellent Series 2000 monopod with its trigger grip head for easy adjusting both in altitude and azimuth.

Optics:

The Oberwerk 15 x 56 ED Ultra is of unquestionable optical quality. It displays a very sharp, high-contrast and colour-pure image all the way from the centre to the field stops. Collimation of the barrels was spot on. Chromatic aberration is vanishingly low across the vast majority of the expansive 70-degree apparent field of view, with only the outer extremities showing up a little lateral colour. The extent to which chromatic aberration has been suppressed was immediately apparent when I compared it to the view through a tripod-mounted 15 x 70 Helios Apollo, which showed much higher levels of colour fringing on the same terrestrial targets. The addition of an FK-61 low dispersion objective element sure works wonders reducing blue/violet fringing to an absolute minimum. 

As well as great edge sharpness from the field-flatteners, the Oberwerk 15 x 56 ED Ultra has very low pincushion distortion in the outer field, which should endear it those who like to study architectural features on buildings. At this high magnification, the 15 x 56 serves up a powerful 3-D effect in the middle distance owing to the large separation of the objectives, increasing the spatial information received by the eye. 

Pointing the instrument at a bright street light after dark revealed only very slight internal reflections in the Oberwerk 15 x 56 ED Ultra. It also performed very well against natural light, with excellent control of glare. 

Notes from the Field:

I measured close focus with a laser rangefinder at 17.4 metres: just a little longer than advertised. The instrument feels great in my medium sized hands. For extra hand-held stabilisation, I found holding the end of the barrels near the objective lenses to afford the most relaxing views. 

The extra reach of a 15x glass came in very handy in the identification of smaller birds at my local pond. On one occasion, I glassed a Common Teal( not so common around these parts), and a Little Grebe which were easily identified with the pin sharp, high-magnification views served up by the Oberwerk ED Ultra.  

I also found this glass ideal for monitoring a Grey Heron nest in a conifer tree just beyond my back garden. To get a good view, I needed to set up about 150 yards away and the 15x afforded me a perfect perspective far enough away so as not to disturb them. 
On another afternoon walk along a quiet country road, I chanced upon a small bird, perched on a prominent branch of a hedgerow about 30 metres in the distance. At first glance, I thought it was a Sparrow, but once I tweaked the focus on the eyepieces on the Oberwerk ED Ultra 15 x 56, I was enthralled to discover that this was a species I had never laid eyes on before: a beautiful Reed Bunting, in all its glory!

A large and powerful glass such as the Oberwerk 15 x 56 ED Ultra really comes into its own monitoring expansive, open waters. I took the instrument over to Balmaha, on the shores of Loch Lomond, one bright morning, to scan the waters for wildlife. Sure enough, I soon chanced upon a small group of noisy Greylag Geese as they took to flight, low, over the waters. I used my monopod to obtain a rock steady view as they made their approach, passing us by about 50 metres out from the shore. Further glassing of the loch showed up some Whooper Swans, leisurely swimming near one of the islands. The excellent optical quality and generously wide field of view made their identification easy with their long, elegant necks and bright yellow bills gleaming in the weak, late winter sunlight. 

I can report one minor niggle with the Oberwerk ED Ultra: the rain guard is a nightmare to put on while the rubber eyecups are folded down. As a result, I used a better fitting guard during all my field work.

Adventures Under the Stars:

I chose the Oberwerk ED Ultra 15 x 56 not only for its excellent daylight performance, but also to explore its potential under the starry heavens. My previous experience with other 15x and 20x glasses with 70mm or 80mm objectives had whet my appetite for observing many of the showpiece objects of the winter sky. And it didn’t disappoint!

First a few words about the specifications of the instrument. My extensive prior experiences with a Nikon EII 10 x 35 convinced me that celestial objects look their best with smaller exits pupils. The sky background is darker in these sub-4mm exit pupils but the extra aperture of the 15 x 56 gathers plenty of starlight, making open clusters sparkle beautifully against the night sky. Furthermore, the complete absence of even slight diffraction spikes in this high-quality Porro prism binocular produces comely, pinpoint stars that are most endearing to the eye. As I explained in my book, Choosing and Using Binoculars, another advantage of smaller exit pupils is that they use the best part of your eye to image the subject. 

My first target was the Moon. I’m delighted to say I’ve observed it through much of its waxing phases, from slender crescent, all the way to its brilliant fullness. The view through the ED Ultra is superb: clean, crisp and with absolutely no colour aberration in the centre of the field. Only by moving the Moon to the edges of the field of view did I see some very modest lateral colour: blue nearest the centre and yellow furthest from the centre. 

Indeed, lunar details, particularly leading up to first quarter phase, were arguably the finest I’ve ever seen in a larger aperture binocular! 

There is a modest drop in illumination near the field edges but the image remains tack sharp even at the field stops. Jupiter is also a great test for false colour fringing and I was relieved to see that its tiny creamy white disk showed none across much of the field of view. 

Exploring darker skies with no Moon on the sky, I tested how well Arcturus looked as I moved it from the centre of the field to the edge. The field flattening optics built into the eyepieces certainly were doing their job, as the bright orange star remained tightly focused throughout. 

I enjoyed wonderful views of the Belt Stars of Orion and the magnificent Sword Handle, the generous AFOV of the ED Ultra presenting exceptionally relaxing and immersive vistas. The views served up by the Ultra ED take you well beyond the performance level of a 10 x 50. The Pleiades and main parts of the Hyades were glorious, sinking into the western skies during late winter. With the constellation of Cancer now at the meridian, I enjoyed framing the beautiful Beehive cluster at the heart of Praesepe, which was just framed by the 4.7 degree true field of the binocular. 

I cherished many spell-binding evenings lying back in a zero gravity chair, handholding the instrument, studying the Perseus Double Cluster and the blizzard of stars surrounding Alpha Persei. Kemble’s Cascade in Camelopardalis approached the zenith in early February. Now orientated north to south, its visually stunning linear array of suns dominated the field of the ED Ultra, with room to spare. 

Bright Messier open clusters were impressively rendered in the 15 x 56 too: M35 in Gemini was well resolved, as were M36, 37 and 38 across the belly of Auriga.  With the arrival of Leo near the meridian late on March evenings, the ED Ultra made light work of  picking up the Spring galaxies of M95, 96 and 105 in the same field of view. The generous light gathering power of this instrument was also able to easily glass the bright galaxy pair – M65 & 66 some 8 degrees further to the east. 

One final reason I settled on a 15 x 56 format is that it serves up far more aesthetically pleasing views of the twilit heavens. From mid-May through mid-July, there is no true darkness at my far northerly latitude(56 degrees north). Having a smaller exit pupil renders the background sky darker, allowing the summer stars to be viewed with more contrast and thereby enhancing the views. I ‘discovered’ this while using a 10 x 35 Nikon Porro, and very much look forward to seeing what this much larger and more powerful glass will do during my summer vacations.

Conclusions & Recommendations:

The Oberwerk Ultra ED 15 x 56 has proven to be an exceptionally versatile performer in my experience, being of great utility both in daylight applications and under the stars. While a monopod or tripod can be employed to obtain the most stable views, it’s also small enough to be enjoyed hand-held for extended periods of time. 

The Oberwerk Ultra ED series takes Porro prism binocular design to new heights of optical performance, with excellent colour correction, wider fields of view, much improved contrast and thoroughly immersive flat field technology. These advances are also coupled with superior ergonomics with their robust, magnesium alloy chassis,  improved 3-point floating plate prism housings and sealed, gas-purged interiors. I’m especially pleased to see that Oberwerk now back these instruments up with an extended 5-year warranty too, which will only serve to improve consumer confidence. I would heartily recommend the 15 x 56 Ultra ED to outdoor enthusiasts and amateur astronomers alike, keen to get the best bang for their hard-earned bucks, and which likely compares favourably to the best roof prism models on the market, but for a fraction of their high retail prices.

 What’s not to like?

Dr Neil English discusses many more binocular models from all genres in his new book, Choosing & Using Binoculars.

De Fideli.

A Work Commenced January 24 2025

Having throughly enjoyed a world-class 10 x 50 binocular for stargazing, in the embodiment of the Sky Rover Banner Cloud, for some time now, I began to wonder what a step up in aperture and magnification might do for studying my favourite deep sky objects. I’ve had some limited experience with Celestron’s  entry-level large binocular: the SkyMaster 15 x 70. This basic instrument revealed some showpiece objects in the night sky such as, the Pleiades and the Orion Nebula in amazing detail: far more, in fact, than any 10 x 50 could show. But it had its drawbacks. For one thing, only the central 50 per cent of the field was acceptably sharp. The build quality wasn’t the most robust either. Long term use would likely result in the barrels losing collimation, and I was also conscious that the binocular was not operating at its advertised aperture of 70mm – more like 63mm in fact. 

That led me to try out a number of other models to assess their optics and build quality. The first model I tested was the Celestron SkyMaster Pro 15 x70. Retailing for £215, or twice as much as the entry-level SkyMaster model, it sports a much more robust build quality. Performing a flashlight test, by directing torch light through the eyepiece and measuring the diameter of the circle of light projected out from the objective indicated that it was indeed operating at its full 70mm aperture.  However, after mounting the instrument on a sturdy Oberwerk 2000 monopod with its excellent trigger grip ball and socket mount, my impressions of its optical performance strongly suggested that it had the same optics as the basic non/pro model. Stars viewed within the inner 50 per cent of the field of view were crisp and sharp but showed the same distortions as the entry level SkyMaster 15 x 70 model in the outer portion of the field. This was disappointing to me as I did expect an improvement in optical performance for this price hike. 

I was also less than impressed by the supplied soft carry case, which I judged woefully inadequate to store the instrument for the long term. This class of instrument definitely deserves a proper carry case if it’s going to be used  regularly. 

Next, I bought in the Opticron Oregon  20 x 80. Retailing for just £159, I was delighted to see that the instrument came in a sturdy, black foam-lined case. I was also surprised by its relatively light weight, tipping the scales at 2.2 kilos. The focus wheel was very smooth and responsive with no free play. Conducting the same torch light test showed that it too was not operating at its full 80mm aperture but only at 74mm, a result in keeping with astro binocular author, Stephen Tonkin, who measured his unit at about 75mm. 

Optically, the unit I acquired performed very well indeed. Even though it has a smaller field of view than the lower power Celestrons at just 3.2 degrees, it showed a much larger sweet spot, with 80 per cent of the field displaying pin sharp stars and even at the edges, stars remained acceptably well presented. Indeed, this 20 x 80 showed me arguably the finest view of the Andromeda Galaxy(M31) I have yet seen in any telescope or binocular. The big 80mm Opticron Oregon represents excellent bang for buck, and is recommended for those on a strict budget. For me though, it raised the same issues I had with the entry-level SkyMaster 15 x 70: under sized prisms and overly light build quality. Still, I was in two minds about letting it go: the views I had of M31, M33, the Sword handle of Orion and the Pleiades, were superb! That extra magnification and smaller exit pupil presented lovely, dark sky hinterlands with sparkling starlight filling the field of view.

Mindful of acquiring high quality optics and a robust build quality, I chanced upon a lightly used Helios Apollo 15 x 70 for a good price and pulled the trigger on it. When it arrived in its custom aluminium hard case, I was mightily impressed by its excellent build quality. This is one chunky binocular weighing in at 2.45 kilos. It has a thick rubber armouring and a fully broadband optical specification. The significantly increase in bulk is attributed to its full size prisms, which deliver extremely bright and sharp images across its 4.4 degree field. Further research indicated that its light transmission is a whopping 94 percent! 

Unlike the usual centre-focus of the aforementioned binoculars from Celestron and Opricron, the now-discontinued Helios Apollo 15 x 70 comes with individually focusing(IF), eyepieces, which take a bit of getting used to! But with practice it becomes second nature.

.

Having to individually focus each eyepiece makes watching wildlife in the near and middle distance quite challenging but for fixed targets it’s not a big issue. The Helios excels at studying targets over long ranges where substantial changes in position can be enjoyed without refocusing. Optically, it’s a good step up from either the Celestron or the Opticron, showing more punchy, higher contrast images with noticeably better control of chromatic aberration. 

The Helios Apollo really struts its stuff under the stars though, where all targets are effectively at infinity. That said, there is a slight difference in best focus when observing celestial targets at low and high altitude. I quickly found that I could achieve a workable compromise here simply by setting the focus on stars situated at mid-altitudes. Views of the showpiece celestial objects are very impressive in the Helios Apollo. It serves up the same 4.4 degree field as the Celestron but exhibits a much larger sweet-spot. That said, performance beyond about 70 per cent of the way from the centre falls off very quickly, so much so that stars at the field stops are quite distorted. Still, I found the quality of the views noticeably superior to the Celestron and I enjoyed many hours studying the Beehive Cluster, the Open Clusters, M35 , M36, M37, M38, the Sword Handle and Belt Stars of Orion. Kemble’s Cascade is beautifully presented within its modest field. The Double Cluster is a mesmerising sight high overhead on a dark winter’s night. Centring Alpha Persei in the field of this big binocular reveals a blizzard of stars shining across the cold, dark of interstellar space. You can spend countless hours panning the winter Milky Way from Monoceros in the south to Cygnus low in the north. 

Having said all that, all these binoculars have their limitations. For one thing, chromatic aberration can prove bothersome to more than a few individuals. Having enjoyed a new breed of ultra flat field binoculars with ED glass prescriptions in smaller apertures, I can immediately see why a wider, flatter field would appeal to many observers of the night sky. Thankfully, there are welcome signs that this market, once the preserve of premium, so-called ‘Alpha’ brands, is now experiencing revolutionary new models from Sky Rover and Oberwerk, for example, which incorporate extra low dispersion glass and field flattening optics, can now be purchased at prices that won’t break the bank. And based on my experiences with this trio of binoculars, I can readily see one of these new models having a permanent home in my binocular arsenal. 

Watch this space!

Read more about binoculars of all genres in my latest book, Choosing & Using Binoculars: A Guide for Stargazers, Birders and Outdoor Enthusiasts.

De Fideli.

A Work Commenced October 5 2024

Preamble

For the past few years I’ve been using a very good 10 x 50 Opticron Porro prism binocular, which has served me well as a longer range terrestrial magnifier and also for conducting astronomical observations. I chose this instrument for its great build quality and bright and sharp optics. It’s small field  of view(5.3 degrees), was enough to frame nearly all the celestial objects I visit throughout the observing year. This size of field also pretty much guaranteed a fairly flat field from edge to edge, keeping stellar images tight and sharp no matter where they’re placed within the field. Back in May however, I bought in an amazing new high-performance roof prism binocular: the Sky Rover Banner Cloud(SRBC) 10 x 50 for review, and its quality literally stunned me. This instrument sported an ultra-flat field, fully double the size of my old 10 x 50 and with excellent colour correction. And while I was able to demonstrate its daylight capabilities in Part I( see the preamble above), I was unable to evaluate its night sky performance owing to the encroach of summer twilight which graces the Scottish landscape between May and the end of July, during which time there is no proper darkness, with only the brightest stars visible in the heavens. 

A Trip to Italy

During early July, our family took off on vacation to northern Italy, basing ourselves in a small commune called Revine Lago, Sottacroda, in the foothills of the great Dolomite Mountain Range, and right in the heart of the Prosecco wine cultivation region of northeastern Italy.

With a climate of hot summers and frequent rain, the area is lush with vegetation. I brought along the 10 x 50 as well as its smaller sibling, the 8 x 42 SRBC, to do some daytime birding and visual astronomy after dark. It was also an ideal environment to test the hardiness of these instruments as they were exposed to dust and intense summer heat, where daytime temperatures soared to well above 40C in direct sunlight. I can report that both instruments coped admirably in these hotter, dustier conditions. 

While most of my birding was conducted with the smaller 8 x 42 glass, I also found myself using the larger 10 x 50 SRBC quite a bit at my local birding patch, overlooking Marine Lago, a small freshwater lake just a kilometre’s walk from our holiday home. For example, while the 8 x 42 frequently picked up some birds fishing the lake far from shore, it was difficult to make a reliable identification, as they remained small in the huge field of view of the 8 x 42, I was able to use the higher power of the 10 x 50 instrument to tease out more detail. And it paid off! These turned out to be Great Crested Grebes, a species I’ve never personally encountered before. 

Both the 8 x 42 and 10 x 50 are extremely stable in my hands. I can hold the 8 x 42 almost rock steady owing to its long barrels and excellent inertia. The 10 x 50 is marginally less stable, of course, more due to the magnification than the weight. My own experiences with lower mass models has definitely shown me that they are less stable at any given power. And if it’s a windy day, I’ll always opt for a heavier glass. This is a very overlooked phenomenon in my opinion, as many folk mistakingly opt for smaller, lighter glasses that are easier to transport. But in my book, optimal inertia overrides such concerns under most conditions.

In early July in northern Italy, sundown occurs shortly after 9 PM local time, although full darkness doesn’t come until after 11 PM. Venturing out about 10:30PM to assess sky conditions, I was greeted by a truly amazing sight: fireflies! Apparently, this location provides the exact hot and humid micro environment for their thriving. I stood in sheer amazement as they flashed in front of my eyes, flying off to gather in nearby bushes. By 11:30 PM they had vanished!

Sky conditions were not as dark as I’d have liked though: a solid Bortle 4, a little bit brighter than my skies in rural central Scotland. Nonetheless, I made full use of the true darkness beginning with Sagittarius and Scorpius well placed in the south around local Midnight. These constellations are too low in the sky at my far northerly latitude of 56 degrees north, so I relished the opportunity to preferentially observe them, together with some selected targets in Ophiuchus. Sitting comfortably in a reclining chair I used the 10 x 50 hand-held to drink up the views. The instrument picked up the rich river of Milky Way starlight coursing through Sagittarius, looking ‘downtown’ as it were, into the centre of our galaxy. Sweeping northwest of the constellation’s brightest luminary, I moved the glass over the Teapot asterism and then on to the Spout, placing Lambda Sagittarii on the eastern edge of my binocular portal, where the 10 x 50 SRBC’s great field of view allowed me to make out the tidy globular cluster M28, and further west, the soft, ghostly light from both the Lagoon(M17) and Trifid Nebulae(M20), with the bright open cluster M21 above them to the north. A delightful view if ever I’ve experienced one!

Moving further west into Scorpius, I centred the bright ruddy star, Antares, and immediately picked up the faint glow of the magnificent globular cluster M4. Spanning an area roughly the size of the full Moon, it’s the closest cluster of its kind to the solar system – a mere 7,200 light years from the solar system. Most of them are situated far out in the halo of our galaxy. Just to the north of Antares, I could see the comely triple system Rho Ophiuchi, arranged in a neat little triangle.  I forsook looking further south towards the celestial gems in the Scorpion’s tail owing to the encroach of a light dome from Vittorio Venito, about six miles to the south of our commune.

Positioning my binocular field between northern Sagittarius and northern Scorpius, I examined the region of sky around Theta Ophiuchi, when I quickly chanced on the pretty binocular double 36 Ophiuchi, with its golden primary and fainter white secondary. In the opulent 7.5 degree field of the 10 x 50  SRBC, I picked up the faint glow of yet another summer globular cluster – M19 off to its west. Ophiuchus has many resplendent globular clusters. Centring Marfik and panning slightly in a southeastward direction I was able to bag two more in the same field: M12 and M10 – both about 12 billion years old! Splendid!

The great river of stars of the summer Milky Way was plainly visible overhead and, sitting back in a recliner, I aimed the 10 x 50 SRBC at Sadr in the heart of Cygnus. The view was stunning! Myriad stars of various degrees of glory filled the field, remaining sharp pinpoints from edge to edge. The dust obscured region immediately around Sadr provided some gorgeous contrast surrounded by a blizzard of faint stars. I had to have a quick look at the fetching colours of O^1 and O^2 Cygni. Their beautiful hues stood out starkly against a coal black sky.

In the following days, we hooked up with my family to attend my nephew’s wedding in the grounds of the beautiful medieval fortress of Castello San Salvatore on the afternoon of July 9. 
 

A beautiful crescent Moon greeted us in the sky after sunset. Once we got home, I fetched the 10 x 50 for a quick peek. And I wasn’t disappointed: she was marble white with no colour fringing in the centre of the field,  the vast southern highlands bristling with craters. It was a fine ending to a most beautiful day!

After a few days in Venice, we returned home to the cool of Scotland. It was a great experience but ultimately too hot for my liking.
Both SRBCs coped admirably though in the intense Italian heat, serving up delightful views by day and by night.

Astronomical Forays under Scottish Skies

While the 10 x 50 SRBC is good to go for short, hand-held astronomical viewing, it certainly benefits from stabilisation using either a tripod or monopod, neither of which were available to me on the Italy trip. For all of my observations here in Scotland, I opted to use the extremely robust and well designed Oberwerk Series 2000 monopod, with a trigger grip mechanism built into the ball & socket mount, which enables the user to alter both the altitude and azimuth movements very easily. At its full extension, it allows six footers like me to observe targets fairly comfortably, even when they are situated near the zenith. This kind of stabilisation rig greatly facilitates studying astronomical targets for longer periods, reducing fatigue and revealing fainter objects within its vast field of view.

Beginning my observations in mid-August, with the return to true dark skies to our latitude, the circumpolar constellations of Cassiopeia and Perseus are already well placed high in the eastern sky after midnight. 

The Milky Way runs richly through Cassiopeia and the 10 x 50 revealed stunning panoramic views within its generous field. To put this somewhat in perspective, the SRBC field is much wider than the 6.6 degree field of the Swarovski EL 10 x 50 and it’s even a tad wider than the newly-launched NL Pure 10 x 52(7.4 degrees)! Couple this with an ultra-flat field and excellent control of chromatic aberration and you can begin to appreciate just how compelling the views are through this instrument.

My first sweep through Cassiopeia with the 10 x 50 really thrilled me. Starting at Ruchbah, sparkling in its striking blue-white light, revealed a few beautiful star clusters in the same field of view, most notably M103, with the Owl(or ET) cluster(NGC 457) off to its south southeast. Several other fainter clusters showed up in the same starfield. After admiring the prominent orange colour of Schedar, I followed a line through to Caph where I picked up the prominent misty patch of M52 about 6 degrees off to its northeast. About 3 degrees south of Caph, the same field easily picked up the open cluster NGC 7789 spanning the size of the full Moon. Some observers have remarked that it looks like the head of a tailless comet. I certainly can’t argue with that description! Scanning the area between Gamma Cassiopeiae and Caph easily picked up the smaller star clusters NGC 129 and 225 in a rich background of Milky Way stars.

Before leaving Cassiopeia, I noticed the bright star, Capella, had reached a decent altitude in the northeast. Then aiming the 10 x 50 at a spot roughly mid-way between Epsilon Cassiopeiae(the fainter star marking the tip of the Wonky W) and Capella, I was quickly able to bag Kemble’s Cascade in Camelopardalis- a remarkable line of about 15 faint stars extending over 2.5 degrees, with a single brighter star marking its centre(almost!). The cascade ends by bifurcating into two distinct starry patches, one of which is marked by a compact 6th magnitude open cluster, NGC 1502. Doubtless, the great light gathering power and huge field of view of the instrument greatly facilitates finding this showpiece object easily and quickly.

By October, Perseus is very well placed for observation high in the eastern sky. Pointing the 10 x 50 SRBC at Alpha Persei(Mirfak) serves up a view par excellence. The entire field is peppered with bright stars. Roughly half of the two dozen or so members lie within a mere 2 degrees of Alpha Persei, with the remaining members fanning out in stunning swirls and streams of starlight. Many of the members of this loose open cluster are youthful, hot white stars, yet the excellent colour correction of the SRBC picks up members with a different hues; orange, yellow and creamy white. 

Moving up the sky to a spot roughly midway between Perseus and Cassiopeia the naked eye easily picks out a misty patch that is transformed into yet another visual treat in the 10 x 50: the famous Double Cluster. Steadied on the monopod, the instrument presents this cluster in all its glory but the eye is also drawn to a prominent curving chain of stars moving off northward ending in the enchanting Stock 2 open cluster. The Double Cluster and its rich Milly Way hinterland is arguably one of the most beautiful sights in all the heavens!

Placing Algol, the Demon star, on the eastern side of the field of view, you’ll see the bright open cluster, M34 off to the west. The SRBC resolves about a dozen of the brighter members of this condensed cluster well, with the remaining constituents creating a misty backdrop easily covering the size of the full Moon.

This time of year the constellation of Cepheus looms large high in the northwest and I couldn’t resist the temptation to have a look at one of the most fascinating and colourful stars in the heavens: Mu Cephei, or Herschel’s Garnet Star. By aiming at a patch of sky between Alpha and Zeta Cephei, the large field of view of the view of the 10 x 50 SRBC very quickly picked up its unmistakable deep red hue. It’s a stunning sight in this instrument – glowing across the light years, like the dying embers of coal fire. About one binocular field off to the northeast of Mu Cephei towards Cassiopeia, the binocular showed me the faint but exceedingly rich star cluster Trumpler 37, which spans an area roughly 3 full Moon diameters in area. It’is a lovely sight in the 10 x 50 on a dark, October night. 

Moving round the autumn sky, the Andromeda Galaxy M31 and its satellites, M32 to its south and M110 further away to its north are fine sights in the SRBC. More challenging is M33 in Triangulum. But it proved easy pickings for this wide angle 10 x 50, simply by placing Alpha Trianguli towards the eastern end of the field when the ghostly glow of this face-on spiral galaxy appears to its west, and with plenty of room to spare. 

Waiting until the wee small hours of a dark moonless night, Taurus, Orion and Gemini begin to dominate the eastern sky. Mighty Jupiter rises early with the stars of Taurus and shines like a bright, distant lantern with its steady, creamy white light. The stabilised 10 x 50 easily shows the ephemeral dance of its four large Galilean moons, constantly shifting their positions hour by hour, as they orbit the giant planet. Mars rises later, its dimmer but unmistakable ruddy hue seen just under Wasat in the midsection of the Twins. 

Auriga, the celestial Charioteer, is also very well placed at these ungodly hours of an October night. The three Messier open clusters, M36, M37 and M38 show up beautifully in the SRBC, within the same field of view, with M36 being partially resolved into stars.

The Hyades and Pleiades are spectacular objects in the 10 x 50. The horns of the celestial Bull fit comfortably within its large field, and I was delighted to see the lovely open cluster, NGC 1674 to the eastern edge of the same field, something quite beyond the capability of my old 10 x 50 Porro. 

Orion holds many treasures for the dedicated star gazer, but you’ll have to wait until about 4.00 AM this time of year before it approaches the meridian. The Belt Stars and its surrounding cluster, Collinder 70, is a spectacular sight on a night of good transparency, with the familiar Snake asterism showing up prominently. 

Further south, the Sword Handle of Orion is a sight for sore eyes steadied on a monopod, but I also enjoyed studying the lovely group of stars in the north of the constellation- Meissa – a neat little Pythagorean triangle of brighter stars, with a delicate line of three fainter suns linking Lambda Orionis to Phi^1. Incidentally, Meissa lies just north of a line joining bright red Betelgeuse and Bellatrix, which are conveniently separated by 7.55 angular degrees of dark sky. This was a good test to measure the true field size of the 10 x 50 SRBC and, sure enough, they were just too far apart to fit inside the field. 

Finally, at about 4:30 AM, looking east of Orion, Gemini loomed large, with Mars, a bright ‘nova’  decorating its mid-section.  I took the opportunity to seek out the wonderful open cluster M35, clearly fan-shaped, with many of its stars resolved, framed by two beautiful orange stars, Mu & Eta Geminorum, pointing the way in the same field of view. Such an enchanting sight! 

Conclusions

The above observations are but a small selection of celestial objects I visited over the last few months with the 10 x 50 SRBC. Incidentally, a new and thorough review of its 12 x 50 sibling has also been published and is well worth a look!

Starting too early in the evening shows up countless artificial satellites: many dozens seen on a typical evening, with sometimes two or three seen crossing through the same field! As the night progresses, those orbiting at lower altitudes disappear first, with those placed in higher orbits fading out last. Temperatures ranged from a balmy 25C on the warmest nights to a few degrees below zero on the coolest.

Throughout these vigils, the SRBC performed flawlessly, with no change in the kinematics of the focus wheel and no fogging up of the eyepieces and objective lenses due in part to the excellent hydrophobic coatings applied to the exterior lenses. It’s been a joyous experience looking through such high quality light cups, their enormous fields making it much easier to find the more elusive objects visited. Alas, I have as yet not been lucky enough to bag the new comet gracing our western skies after sunset, but I hope to finally glimpse this icy interloper from the Oort Cloud, before it disappears into the cold dark of interstellar space.

Wish me good luck won’t you!

Update December 6 2024: I did manage to see Comet Tsuchinshan on the evening of October 14 and again on October 17 using the 10 x 50 SRBC. Past its prime I know, but still well worth the effort! Mars moved from Gemini into Cancer on October 20, and in the wee small hours of a very blustery December 6, it was observed just over two degrees north of the celebrated Beehive Cluster. A glorious sight to see right now. It should inch a little closer to the Beehive in the hours to come!

Neil English has been observing the night sky from the tender age of eleven, and has written 8 books about these experiences.

De Fideli.