But even if we (or an angel from heaven) should announce any “good news” to you other than what we have proclaimed to you, let that person be cursed.
Galatians 1:8
And no marvel; for Satan himself is transformed into an angel of light.
2 Corinthians 11:14
Islam is rapidly gaining influence in the West. In this brand new biography, the distinguished Islamic scholar, Dr Robert Spencer, outlines the mythology behind its founder, Muhammad, casting a critical eye on the prophet’s ‘morality,’ as well as asking the question about whether he actually existed.
In this blog, I’ll be posting links every day on various topics of interest to those who value truth over lies in this, the most wicked, godless and depraved of human generations since the Days of Noah.
Back in 2015, I parted company with refractors as my main astronomical viewing instruments, having ‘seen the light,’ as it were, when I acquired a brilliantly simple 200mm F/5.9 Dobsonian from Skywatcher. Once properly collimated and acclimated under good seeing conditions, it significantly out-performed a top-rated 5 inch F/12 refractor on pretty much everything. The experience radically changed my perception of the true value of refractors, particularly when scaled up beyond 5 inches.
Over the last decade, I’ve made a series of modifications to this 200mm Newtonian, called Octavius, owing to its 8 inches of aperture. The primary mirror from Skywatcher was good but I decided to replace it with a true 8-inch (203mm) F/6 Ultra Grade mirror with an accuracy exceeding 1/10th wave PV from Orion Optics UK, which also came with state of the art reflective coatings – HiLux enhanced aluminium – increasing the mirror’s reflectivity from 85 per cent to over 97 percent across the visible spectrum.
I then upgraded the secondary mirror by ordering up a smaller(1.52 inches) and more optically flat Antares unit with a 1/15th wave PV surface accuracy, whilst also reducing the central obstruction to less than 20 per cent by aperture.
Like the primary, the small secondary mirror came with enhanced aluminium coatings as standard, to maximise image brightness. Because it’s such a small and lightweight mirror, I could attach it to the stalk using double-sided tape.
My own personal experience with enhanced aluminium coatings is that they have much greater longevity compared with standard coatings. Indeed I have older mirrors treated with HiLux that are 10 years old and show no signs of deterioration despite regular use in my damp Scottish climate. The somewhat flimsy secondary housing on the original SkyWatcher 200P was removed and replaced by a much more rigid and solidly-built structure manufactured by the German company, BackYard Universe.
The secondary holder has a diameter of 40mm – slightly larger, in fact, than the 38.6mm elliptical flat mirror – giving a minimum central obstruction of 19.7 per cent. Of course, If I so desired, I could have installed a low-profile focuser and decrease the secondary obstruction to just 10 per cent using a even smaller secondary, not to mention the need to redesign the spider structure. But in the end I decided against it, as I wanted to create a more all-purpose visual instrument rather than a specialised lunar and planet killer. And in any case, optical theory informs me that once the central obstruction falls below 20 per cent or so, the effects are almost indiscernible from a non obstructed optic of the same aperture.
I did however replace the original single-speed rack and pinion focuser on the SkyWatcher Explorer P after ten years of heavy use, with SkyWatcher’s dual-speed Crayford focuser, which allows me to achieve smooth and precise micro-focusing on high resolution targets.
I also attached an inexpensive USB type cooling fan to the rear of the primary mirror which helps remove the boundary layer of warm air accumulating above the surface of the mirror, to help keep the images as crisp and detailed as possible.
The interior of the tube is lined with cork and overlaid by matt black flocking material to further enhance its thermal properties, as well as maximising image contrast.
The telescope sits in the original lazy susan altazimuth mount with the stalks under its base fitting into some pre-cut holes I made in an inexpensive plastic water butt. This raises the height of the telescope further above the ground providing a supremely comfortable standing height – I’m a six footer – for all my astronomical observations. And that brings me to the second reason for abandoning refractors- I hate sitting down, huddling over an eyepiece, straining my back while trying to study a target located high in the sky. Those kinds of observations are much more comfortably executed while standing up. Indeed, I even use my travel scope- a high quality 130mm F/5 Newtonian placed on an altazimuth mount- in exactly the same way i.e. standing up. Once I got used to standing with my Newtonians, there was no going back to refractors.
Just as any fine musical instrument benefits from occasional tuning up, so too does Octavius. At F/6 collimation is very easy, so easy in fact that it only requires a simple collimation cap to get you 90 per cent of the way there, and quite often better. The final tweaking is done manually by performing a star test at high power and making those final adjustments using the collimation screws on the primary mirror. It’s quick and easy, taking only a couple of minutes to get perfect alignment of the optics.
The more rigid secondary structure has greatly helped to maintain precise collimation from night to night, so much so that the instrument only needs occasional tweaking when moved from its indoor storage space to the outside air. That’s how it should be!
So how good are the optics? In a word- superb! But to elaborate: star testing at 200x under good conditions shows identical diffraction patterns inside and outside focus. Stars focus down to tiny, round Airy disks. By far the biggest benefit has come from the primary mirror. On the night the new primary arrived back in January, I was immediately able to discern the improvement on Jupiter. The new mirror snapped to focus better, showed more contrast and routinely revealed subtle details on the Giant planet that I had only vaguely discerned using the original mirror. Magnifying the first quarter Moon up to well beyond 400x showed no image breakdown whatsoever. The image below is a single shot image of the first quarter Moon taken with the Svbony SC001 2 Megapixel imaging camera, on the evening of May 3 2025, showing some very fine details.
Know Thy Telescope
Modern Newtonian primary mirrors are figured into the shape of a parabola. But why a parabola? Some analytical geometry can help us understand why:
In contrast, a spherical mirror has no fixed focal point but can approximate a parabolic shape if the focal ratio is made very large. Unfortunately, as the aperture increases, the focal lengths needed for spherical mirrors to work well very quickly become impractical.
Optimum Aperture for Resolving Binary Stars.
Octavius is used mainly as a lunar, planetary and double star scope, although I also use it for deep sky observing too. One of my passions is double star observing, at which Octavius excels. Indeed, with a decade of experience with this telescope, I’ve come to accept that it’s very close to ideal for observing tricky binary systems reaching pairs less than 1” separation.
The following analysis is based on the work of Michael Greaney from chapter 25 of the book, Observing and Measuring Double Stars(2nd edition) which was incorrectly printed( the errors from which were reported by yours truly ,to the editor, Bob Argyle, at the Institute of Astronomy, Cambridge, UK).
According to Sidgwick, the maximum useful magnification of a telescope is approximately 28D^0.5 where D is the aperture of the telescope in millimetres. This was empirically derived, so has taken the effects of atmospheric seeing under British skies into account.
On the other hand, according to the work of the late professional double star astronomer, Dr Paul Couteau, the minimum useful magnification for resolving close binary stars is twice the resolving magnification of the telescope, which turns out to be D in millimetres.
There must exist an optimum value of D between the maximum useful magnification and the minimum useful magnification. If we express this as f(D) = 28D^0.5 – D
Then differentiating with respect to D gives:
f’(D) =14D^-0.5 -1 = 0 for the optimum, which turns out to be D =14^2 =196mm.
This result is just shy of 8 inches, the same aperture as Octavius.
Octavius, Optimus!
A Mid-Summer Night’s Dream
Octavius in summer twilight.
I’ve noted the efficiency of the 8-inch F/6 Newtonian many times over the years, but as a case in point, I used the instrument on two nights just after the summer solstice to resolve some tricky double stars at high power. First on the night of June 24-25 and again on June 28-29 2025. My workhorse eyepiece for this kind of project is my trusty Svbony SV 215 3-8mm planetary zoom eyepiece yielding magnifications of 152x – 406x. As the experienced observer, Alan Dyer, of Sky & Telescope concluded in his review, this is an excellent eyepiece, fully the equal of the Nagler zooms but offered at a much more attractive price. Additionally, I usually have 1.6x, 2x and 3x Barlow lenses handy to boost the magnification as high as 1218x.
This time of year, the twilight limits my observations to a short period of time between 11:30pm and about 1:00am local time, as any later and the sky begins to brighten again. I usually ‘warm up,’ starting with easier pairs such as Epsilon 1 & 2 Lyrae, all four components of which are easily split at 152x in the 8-inch. Moving on to Delta Cygni, which has a faint close companion, Octavius made light work of resolving this system at powers upward of 300x. One invaluable tool I use to enhance the detection of these close, unequal magnitude pairs is a polarising filter, which helps to cut off some of the diffraction ‘gunk’ between the components, in much the same way as an apodising filter works.
From there, I moved over to Aquila, low in the east, and tracked down the sixth magnitude star Pi Aquilae, centered it in my 8 x 50 finder scope and then cranked up the power to 406x, which is sufficient to tease both components – a pair of white sixth magnitude stars separated by just 1.4 arc seconds – and orientated roughly east-to-west.
Confident of good, steady skies, I next trained the instrument on Lambda Cygni – by now high in the eastern sky. Starting at 406x, I leave the star drift through the field, watching with intensity what the image might show me. Sure enough, I began to glimpse the secondary star (magnitude 6.3) almost precisely north of the primary(magnitude 4.7) and separated by a sliver of twilit space merely 0.9 arc seconds apart. Checking Stelledoppie afterwards, I was delighted to see its estimated position angle to be 01 degree, so almost immediately due north of its primary! Cranking up the power to 812x using a 2x Barlow lens gave an even more impressive view: the two stars cleanly resolved, and racing through the field of my un-driven telescope at breakneck speed! How swiftly the Earth moves! Time waits for no one.
At their distance from the solar system, the pair orbit their common centre of gravity every 391 years.
The above was recorded after midnight on June 25 but I was able to repeat the split just a few nights later on June 29. So, two clear nights just after the solstice when the telescope was able to resolve this sub arc-second pair! This might sound unusual, but it’s actually quite typical of our summer sky seeing – and, truth be told, all over the British Isles(having surveyed its suitability across Ireland as well),- here in rural central Scotland!
Unequal Pairs
The Dawes Limit has long remained the empirical limit on the resolution of double stars. Formulated in the 19th century by the celebrated Victorian observer, William Rutter Dawes, it states that the resolution limit for a telescope in arc seconds is given by 4.56/D where D is the aperture in inches. The formula Dawes arrived at was for equal brightness 6th magnitude stars. Thus, Octavius ought to be able to resolve equal magnitude pairs as close as 0.57 arc seconds. But things get more challenging for pairs of unequal brightness. In short the bigger the brightness differential between the stars the harder they are to tease apart.
Of the closer pairs already discussed, the easiest is Pi Aquilae(1.4”), since they only differ in brightness by 0.41 stellar magnitudes. More challenging yet is Lambda Cygni (0.9”) with a brightness differential of 1.53 stellar magnitudes. But at 00.02h on the night of July 17, during a spell of excellent astronomical seeing, I trained Octavius on Zeta Herculis, a yellow-white sun-like star still high in the summer sky just past meridian passage. The secondary is separated from its primary by 1.53” but the magnitude differential is 2.45. Charging the telescope with a power of 650x using my polarising filter, the 8-inch Newtonian was easily able to resolve the secondary immediately due east of its primary( confirmed by consulting Stelledoppie). Another similar test of this kind can be conducted on Propus(Eta Geminorum)during the winter months. With a separation of 1.83” but a magnitude differential of 2.63, this is considerably easier to tease apart.
Why mention close, unequal pairs like these? Well, commonly accepted wisdom holds that Newtonians work best for equal magnitude pairs, but I’ve found this to be another myth promulgated by some members of the amateur community. After studying the work of Christopher Taylor, a theoretical physicist by training, and keen double star observer with a particular interest in resolving sub-arc second pairs using a 12.5 inch F/7 Calver reflector erected on a massive, un-driven altazimuth mount down at Oxford(discussed in Chapter 11 of Argyle’s book previously mentioned), it became clear to me why Octavius does so well on unequal double stars like Zeta Herculis. It has a small central obstruction and vanishingly low spherical aberration- both of which result in transferring substantially less energy from the Airy disk into the diffraction rings, thereby making a faint companion more easily resolvable from its primary. Indeed, Taylor admits as much in his book chapter, by making the point that his century-old Calver mirror was deliberated left under-corrected to help keep track with falling temperatures.
Examining the Airy disks of second and third magnitude stars in Octavius on nights of good seeing, reveals tiny pinpoint stars with a singular ring of moderate size and brightness. In other words: the images are very refractor-like. Perhaps most fascinating of all is the sheer dynamism of pairs like Zeta Herculis. Located a few tens of light years away, the companion to Zeta Herculis orbits its primary in just 34.5 years. That means that its position angle relative to its primary changes significantly in just a few years! Having carried out observations of this system regularly over the last decade I’ve witnessed its rapid movements from one year to the next. How cool is that?
For the record, Tau Cygni, easy to pick up even in summer twilight, and currently separated from its primary by 1.1” but with a 2.75 magnitude difference, presents a similar type of challenge.
A New and Improved Primary Mirror Fan
I’ve dithered for years about whether a primary mirror cooling fan would be worth installing. I’ve generally not encountered much in the way of thermal issues using Octavius, as we experience only small diurnal temperature swings for much of the year, though April and May have brought their problems, with warm sunny days and chilly nights. I generally store the telescope in a dry, unheated shed, just a few degrees warmer than the outside air. However, during the cold winter of 2024-25, I bought a small USB desk fan and affixed it to the rear of my primary mirror using a few layers of double-sided tape. It was powered by a small portable power pack and after several trials,I became convinced that it did clean up the images of Jupiter and Mars in a subtle but consistent way. However, I did perceive some vibrations at the high powers I use for close double stars. I attributed this to the direct attachment of the fan to the mirror.
So I decided to splash out on a dedicated mirror fan manufactured by Austral Solutions, based in Spain. This new fan attaches to the outer tube of the telescope in such a way that it doesn’t touch the primary directly, but blows ambient air onto to the centre of the primary mirror. It’s powered by a 12v DC step-down transformer (user provided)powered from a mains (AC) source. Although this requirement necessitates having a constant supply of electricity, it’s more reliable than the portable power pack I had used with the original fan, which often cut out, especially on colder evenings, over the winter and spring. My results this summer, examining high-resolution double stars, testing various permutations (turning the fan off and on and critically examining the seeing disks) has convinced me that keeping the fan running constantly significantly increases the stability of the Newtonian image.
Finding Fainter Pairs
By late July, the skies above me become noticeably darker, allowing me to better track down fainter binary star systems. One example is Mu Cygni, which can now be tracked down using my finder scope on the eastern flank of this large, summer constellation. My notes show that I had not visited this system for about six years, so I was excited to pay a visit to this old friend. On the night of July 23-24, I trained Octavius on Mu, which is easily identified by virtue of a wide, unrelated 7th magnitude star off to the east of it in the finder telescope. Charging Octavius with a power of 406x(fan running), I was greeted by a beautiful sight: a pair of white suns separated by 1.6”, the primary having a magnitude of 4.8 and the secondary- 6.2-roughly due north of it. I don’t remember this system to be much of a challenge for a good 4- or 5-inch refractor employing high powers back in the day. Clearly the secondary is closing in on the primary, making it more challenging than I remember.
In addition, on the same night, I trained Octavius on Iota Cassiopeiae, now at a decent altitude off to my northeast, and cranked the power up to about 200x to reveal this beautiful triple system for the first time this season. A nice way to end my vigil on this rather cool July night!
A Return to Dark Nights
By the last week of July, the skies are turning noticeably darker after sunset here in rural central Scotland. On the night of July 29-30, I enjoyed a reasonably calm, clear sky and by half past midnight local time, I could once again see the faint glow of the summer Milky Way coursing its way through Cygnus and Cassiopeia. Seeing was only average though, so no high-resolution double star observing was conducted. Instead I turned Octavius on some familiar summer deep sky objects. To view some of the larger objects on display, I employ longer focal length 1.25” eyepieces like my 22mm (70 degree AFOV) yielding a low power of 55x in a true field of 1.26 degrees and a medium power from my 15mm (68-degree AFOV) which yields a power of 81x in a 0.84 degree field. The reader will note that I do not employ 2” eyepieces for lower power wider FOV viewing for two principal reasons: I strongly dislike having to switch between the 1.25” and 2” formats, and the lower powers of these longer local length oculars shows up the astigmatism in my right observing eye which I find distracting when used without eye glasses. That said a 1.26 degree field is more than enough to enjoy pretty much all of the objects I visit with Octavius. If I want larger fields, I turn to my large, 15 x 56 binoculars.
I first turned Octavius on the Ring Nebula(M57) in Lyra, its ghostly glow coming through nicely at 152x. Then moving into Hercules, I quickly located both M13 and M92, both globular clusters located far out in the halo of our galaxy. Although these are best resolved at powers of 150x to 200x, tonight I was happy to admire these beautiful baubles of ancient starlight at 81x using my 15mm eyepiece.
After having quick looks at easy double stars such as Gamma Delphini and the colourful, O1 and O2 Cygni and the famous 61 Cygni, I trained the telescope on the wide but rich open cluster M39 at the head of Cygnus, enjoying the dozens of pinpoint stars strewn across the field of the 22mm eyepiece, and set against a rich Milky Way hinterland. By 1:00 AM local time, Cassiopeia was just clearing my rooftop and I had hoped to catch a glimpse of the famous Double Cluster in Perseus. Alas it was still too low for me to access it. It will have to wait a wee while longer before I can view this spectacular object in my trusty 8 inch Newtonian.
The Assault on Tau Cygni
The night of August 9-10 was cool and breezy, but the sky was clear, with relatively calm twinkling stars..The full Moon culminating low in the south. I fielded Octavius at around 10:30pm local time and tested sky conditions by looking at a few binary systems of increasing difficulty. First I targeted Delta Cygni and was delighted to get a very clean split at 244x. Then I moved over to Lambda Cygni, cranked the power up to 650x and once again managed to split this system with relative ease. Confident that this would be a good night to try my hand at Tau Cygni, I began by observing the star at powers up to 406x but with not a lot of success. Patience is a virtue, however. The system had a few hours to go before it reached its highest altitude crossing the meridian. Leaving the fan running continuously, I covered the optics and ventured inside for a while before returning to the telescope every half hour or so. With each attempt, I could see that the appearance of the Airy disk of the 4th magnitude yellow white primary looked better and better as I was looking through less atmosphere. After midnight, using a power of 812x , I got my first glimpse of the secondary with a current separation of about 1” off to the SSE of the primary but it was only tentative at this stage. By about 1.00AM local time, I ventured out again, charging the instrument with a power of 812x and positioned the star on the east side of the telescopic field. In moments of superior seeing, I could make out a faint disk in the same position I had glimpsed earlier, but now it was more steadily held. Reaching for my 3x Barlow and switching it out with my 2x Barlow, the telescope could now deliver a power of 1218x – crazy I know! To see this system at such high power on an un-driven mount, you start at the lowest zoom setting (8mm with a 3x magnification boost), placing the star at the eastern edge of the field, focus as finely as possible and then crank the power upwards toward 1218x. The strategy paid off! At these extremely high powers, I was better able to tease the components apart and record its position relative to the direction of drift. After I had made a sketch, I consulted Stelledoppie and was delighted to see that the companion was in just the right position it should be in August 2025. I note the last measure was made back in 2017 when the estimated position angle was 190 degrees. Since then the 7th magnitude companion had moved eastward in its orbit round the primary. Back in 2017, it was located off to the SSW but now it was in a SSE direction.
This was a thrilling observation: one of the most difficult I’ve tried in quite some time: a companion separated by just 1” of sky but fully 2.74 magnitudes fainter! This would be a severe challenge for a 6-or 7-inch refractor but it was quite doable on a good night here in rural central Scotland, using a fine-tuned 8-inch Newtonian with a sub-20% central obstruction. The sun-like star Tau Cygni B, orbits its primary every 49.5 years.
A Visit to 61 Cygni:
In the same telescopic field as Tau Cygni my 8 x 50 finder scope picks up the lovely pair of orange stars known as 61 Cygni. Even the smallest telescope is capable of resolving these stars and even steadily held 10x binoculars should tease these apart. At 153x Octavius frames these stars perfectly with a nice Milky Way background. The brighter of the two has a magnitude of 5.2 and its companion nearly a full visual magnitude fainter. To my eye both stars exhibit the same orange hue and that’s not surprising as they are both K spectral class dwarf stars with temperatures a little over 4000K. 61 Cygni was all the rage in the first few decades of the 19th century, when astronomers noted their large proper motion, a good sign that these stars were relatively close to the solar system. As recounted in great detail in Chapter 11 of my large historical work, Chronicling the Golden Age of Astronomy, it was the great German astronomer, Friedrich Wilhelm Bessel, who, by 1840, first measured their distance from the solar system to be 10.3 light years away: only 10 percent lower than the modern accepted value. 61 Cygni represents a true binary star system, the components of which orbiting their common centre of gravity every 680 years.
Astronomers have yet to identify planets orbiting these cool, long-lived stars, but in general, unless their planets orbit very close to their parent stars, the chaotic orbital motions of close binary star systems like this generally cause their planets to be ejected from their system over time. Still, in the mind’s eye, I can imagine being on the surface of one such world, watching two golden suns rising and setting in a clear sky. How wonderful it would be to witness such a sight!
About four years back, I alerted the community to an inexpensive series of binoculars – Svbony’s SV 202s – offering optical performance well above what I expected from their price class. Since then, thousands of units are now in the hands of an army of outdoor enthusiasts in Europe, the Far East, the Antipodean, and the United States . So when Svbony decided to give their SV 202 series a makeover, I was naturally curious to see what changes had occurred. I ordered up the 10 x 42 to put it through its paces, and the following is a summary of my findings.
A Great New Look
Although the neat package containing the instrument was the same as before, a cursory examination of the binocular showed some notable changes. For one thing, the rather tough armouring of the original SV202 had been replaced by a softer but thicker rubber substrate that offers a finer grip than the first generation models. In addition, the company’s name is now proudly displayed on the side of the binocular giving it a more classy look.
The next thing I noticed was its very light weight for a binocular in this aperture class. While the original 10 x 42 tipped the scales at just under 700g, the new SV202 weighed in at just 659g, making it arguably one of the lightest 10 x42s I’ve personally encountered!
Another surprise hit me when I started moving the focus wheel; gone is the old metal focuser. Its replacement is covered with soft, indented rubber which is very smooth and responsive. My unit has zero free play or backlash: indeed it’s one of the best focusers I’ve seen in quite a while, certainly better than the original model. A little over two rotations anticlockwise takes you from closest focus to a little beyond infinity – good news for those who suffer from moderate myopia.
The right eye dioptre compensation ring moves smoothly but holds its position rigidly. Nothing fancy here: but it certainly does the job!
The twist-up eyecups have three positions and lock in place firmly with a moderately loud ‘click.’ They are, in fact, just as solid as the original models though, and actually a bit better built than on their flagship binocular – the SA205. Eye relief is fairly generous: I was comfortably able to view the entire field wearing my eye glasses.
The next surprise came when I examined the coatings applied to both the objective and ocular lenses. Gone is the deep magenta bloom used on the earlier model SV202, replaced by more conventional tobacco coloured coatings that are noticeably less reflective than the original.
Like the first-generation models, the objectives are deeply recessed to protect the lenses from the elements as well as stray light.
In the hands the new SV202 ED binocular feels great: easy to grip and easy to wrap your hands round the barrels. And it’s very light weight- more like some heavier 32mm binos I’ve encountered – making it especially comfortable on long walks.
All in all, the ergonomic changes to the new SV202 ED were a very pleasant surprise and most certainly render the instrument more fun to use.
Optics
Examining the image of a bright beam of light from across my living room showed no significant diffraction spikes but did show a few annoying internal reflections. The same was true when I examined a bright street lamp after dark in the distance. This is definitely an inferior result to my findings with the original SV202, which showed far less in the way of internal reflections.
A clue to what was going on ‘underneath the bonnet’ as it were was revealed when I examined the exit pupils seen against a bright indoor lamp. As the images below show, there are significant light leaks immediately in the vicinity of the pupils which were responsible for the only negative finding I picked up in my daylight glassing tests.
The view through the SV202 10 x 42 ED is very good; bright, sharp, high contrast, with neutral but saturated colours. Suppression of chromatic aberration is also excellent. Indeed I was expecting significantly more given that this is a 10x instrument. Glassing through layers of leaves against a bright overcast sky showed up just a trace of lateral colour in the outer 15 per cent of the field. There is some moderate pincushion distortion though, which does help somewhat with comfortable panning. Glassing against the light or placing the sun at an oblique angle to my line of sight did throw up a bit of lens flare but that is probably the only personal issue I had with this unit. Edge of field sharpness was also very good: only a small amount of field curvature softens the image just inside the field stops.
Overall , the Mark II SV202 10 x 42 ED is very impressive when you consider the very reasonable price tag this instrument comes with.
Notes from the Field
I afforded the most comfortable and immersive views by extending the eyecups into the first locking position, as seen in the photographs. Close focus was found to be just over 2m, a significant improvement over the 2.5m advertised. The excellent focus wheel makes finding the sharpest possible view quick and easy. Conducting most of my daytime glassing using 8 x binoculars, shifting back to 10x shows a noticeably shallower depth of field, as you’d expect.
10 x 42 binos are very popular with hunters who need that extra bit of reach or those general observers who enjoy seeing fine details. I did find the instrument a little tricky to hold steady on the afternoon of August 4, when Storm Floris swept its way northeastward across the country, bringing with it inland gusts up to 60mph. A weightier instrument would definitely fare better under these conditions.
Turning the instrument on the August night sky generated impressive views of the starry heavens. The first quarter Moon was tack sharp and without colour fringing inside its generous sweet spot but a very modest amount of lateral colour creeps in: blue on one side of the field and yellowish-green on the other. I did pick up a few internal reflections though as reported earlier.
Star clusters look great in the Mark II 10 x 42ED and goes considerably deeper than any 8 x glass. Collimation is good. I enjoyed observing the Alpha Persei Cluster, the Double Cluster, the Andromeda Galaxy and its fainter satellites, M33 in Triangulum, and the Coathanger asterism in Vulpecula. Lying back in my zero gravity chair I enjoyed tracking down other smaller clusters, panning the Milky Way through Cygnus and Cassiopeia. Because field curvature is so mild, even stars at the edges of the field remain quite well focused – an impressive result for a binocular without field flatteners.
Conclusions & Recommendations
In many ways, the Mark II Svbony SV202 10 x 42 ED is an improvement over the original model, with better ergonomics, a wider field of view, less colour fringing, and lower weight. At its current retail price you’d be very hard pushed to get an instrument this good at twice the price. It remains a solid performer and one of the best bangs for buck on the market today.
Be sure to check it out!
Dr Neil English explores the fascinating world of binoculars in his detailed book, Choosing & Using Binoculars: A Guide for Stargazers, Birders and Outdoor Enthusiasts
For the last few years, I’ve been busy using Svbony’s SC001 imager which I’ve used on a few of their spotting scopes, and most recently with their flagship 100mm aperture SA401 26x-75x APO. As good as it is, it has its limitations. For one thing, the SC001 imager offers a fixed high-power magnification similar to a 6mm eyepiece. For some imagers, this represented too high a power to frame targets easily, especially if your intended target is mobile. Now Svbony has introduced a significantly more versatile camera: enter the SC002.
About the size of a smart speaker, the SC002, is very light so won’t cause any balancing issues with your optics. It consists of a 2 Megapixel webcam built into a larger ABS plastic structure that can be fitted securely to large zoom eyepieces found on spotting scopes and to regular eyepieces (37-56mm diameter). The SC002 can also be attached to binoculars!
Its ability to mate to a wide variety of eyepieces is achieved by rotating the top half of the SC002 which causes three claws to grip the top of the eyepiece. It’s quick and simple, with no other adaptors required. After you download the SC002 App, the camera is switched on by pressing the button on the top of the device. The device has a built in WiFi connection that connects to your phone. As long as you’re within 10m of the imager, the signal is strong enough to operate the scope from your smart phone.
Unlike the SC001 imager, the SC002 offers a full screen but also 1x, 2x or 3x digital zoom. This allows the user to tweak the focus until it is as sharp as it can possibly be. The imager automatically captures the best images but only presents them at full-screen 1x mode. Another excellent feature of the SC002 imager is its ability to connect live to two smartphones simultaneously; one to take images and the other phone to preview the image. The SC002 can also capture live video for up to 2 hrs in 1080P and the data stored on the supplied 32GB memory card. Three shooting modes are available to the user: 1:1, 4:3 or 16:9.
Here are some sample images taken through the SA401100
Next, some photos taken in the field with Svbony’s flagship flat-field ED binoculars: the very capable SA205 8 x 42:
And finally, some astronomical shots taken through a telescope:
All in all, the new SC002 imager represents a significant advance on the SC001. The user can choose how much magnification they wish to employ to frame their photographic subjects, and the digital zoom options greatly assist in finding that perfect focus. Retailing for well under $100 and weighing only 140g, this simple yet ingeniously portable device will greatly enhance your imaging capabilities, not only with spotting scopes, but also monoculars, binoculars and astronomical telescopes alike.
Recommended!
Dr Neil English is the author of Choosing & Using Binoculars: a Guide for Stargazers, Birders and Outdoor Enthusiasts.
Chassis: Magnesium Alloy and Titanium covered in black Vulcanised Rubber.
Exit Pupil: 4mm
Eye Relief: 13.3mm
Field of View: 135mm @1000m(7.74 angular degrees).
ED Glass: Yes-Schott Fluorite
Other Notable Glass: Schott HT
Dioptre Compensation:+\- 4
Close Focus:2.1m advertised, 1.91m measured
Hydrophobic Coatings on Outer Lenses: Yes, AquaDura
Fogproof: Yes
Waterproof: Yes/5m
Accessories:Objective lens covers, rain guard, neoprene neck strap, lens cleaning cloth, padded soft case, test certificate, warranty card and user manual
Warranty: 10 Years
Weight: 535g advertised, 534g measured
Price(UK): £1499
The Leica Ultravid series is one of the longest continuously manufactured binoculars by the prestigious German company, Leica. Introduced in the Black Rubber (BR)form back in 2003, the series was upgraded to the HD series in 2007, which featured Schott Fluorite glass for improved colour fidelity and Leica’s innovative AquaDura hydrophobic and anti-scratch coatings. Finally in 2015, the company introduced the latest version: the Ultravid HD+ series which incorporated Schott HT glass in the prisms which increased light transmission to an impressive 92-3 per cent. In all Leica offer the HD+ series in 8 and 10 x 32, 7, 8 and 10 x 42 and two larger models – the 10 and 12 x 50. This review will discuss the smallest HD + model; the 8 x 32.
My first experience with this series came a couple of years back when I had the pleasure of looking through the 10 x32 Ultravid (UV)HD+ observing birds out on the water of Loch Carron, just a few miles from my home. The owner was so impressed with the binocular that he bought a second 10 x 32 for his daughter. It was here that my concerns about the small size were put to rest, since I was able to hold them very comfortably in my medium-size hands.
The 8 x 32 is an amazingly small and compact model, only 11cm from the end to end with the eyecups kept down. Tipping the scales at 534g, it’s super light weight.
The focus wheel is disproportionately large, making it very easy to manoeuvre using one or two fingers. While there is some inertia getting it moving , focusing is very precise with no free play. This is an improvement over their entry-level model, the Trinovid HD 8 x 32, the focus wheel of which had a small amount of free play. Just over one full revolution clockwise brings you from closest focus to a little bit beyond infinity. The dioptre compensation is accessed by pulling up the top part of the focus wheel, turning the wheel and pushing it back in.
The eyecups can be used in three positions: fully retracted or pulled up through two click stops. Like I said many times before, Leica’s eyecups are amongst the best in the industry. They are supremely comfortable and click rigidly into place.
Eye relief is quite tight on the 8 x 32 though, especially for eye glass wearers. I did test them using my spectacles and I could just see the entire field but it’s certainly not a comfortable experience especially during prolonged field use. Luckily, I don’t wear glasses using my binoculars so it was really a non-issue for me.
Unlike the larger UVHD+ models, the underside of the barrels on the 32mm models have no thumb indents. Over the years, I’ve cultivated a strong disliking for these anyway, so not having them is a bonus in my books!
The objective lenses are nicely recessed with excellent knife-edge baffles to minimise glare when glassing against the light. The coatings are immaculate: giving a faint purple bloom when examined face on but present more of a tobacco hue when seen at more oblique angles.
In the hands, the little Leica UVHD+ 8 x 32 is very firmly held thanks to the textured black rubber armouring, though it’s a magnet for dust, pollen and other airborne matter. I can wrap my little fingers round the front of the barrels while using my ring- and middle-finger to do most of the focusing. It’s also a supremely handsome binocular with a strong retro accent I very much like.
Optics:
Looking at an intensely bright light source from across the room through the Leica UVHD+ showed no internal reflections but I did pick up a moderate diffraction spike. The same was true when I turned the binocular on a distant street lamp after dark.
Next I examined the exit pupils while the instrument was aimed towards an indoor room light. As you can see below the result was excellent: exemplary in fact! Just nice round pupils surrounded by complete darkness!
Credit where it’s due: the view has real ‘gestalt:’ beautiful, arresting: razor sharp, wonderfully contrasted, with vibrant colours. Chromatic aberration is absent in the centre but does show up as lateral colour in the outer part of the field. Being used to larger, flatter fields, I was half anticipating that the 7.74 degree field would be rather restrictive or ‘tunnelled,’ but I did not get that impression. The view is extremely relaxed, especially for a compact model like this.
The Leica UVHD+ 8 x 32 does have more pincushion distortion than I would have liked and the edge sharpness could be better. Finally, when glassing with bright sunshine directly behind me, I noted some annoying reflections off the ocular lens. Thankfully this can be remedied simply by placing a finger over the side of the eyecup.
Notes from the Field:
Make no mistake about it; the Leica UVHD+ 8 x 32 is a study in miniaturisation. A true marvel in both mechanical and optical engineering!
But it ain’t perfect.
Close focus was measured to be 1.91m, closer than the advertised 2.1m, but not nearly as impressive as the super close 0.95m I measured on the Trinovid HD 8 x 32. There are two aspects to the image of the UVHD+ that are noteworthy compared with my main binocular, the superb SRBC 8 x 42: colour saturation and resistance to glare of all kinds.
In the centre of the image, sharpness in both is quite comparable but the colours generated by the SRBC optical system are a little more neutral than in the UVHD+, the latter of which has a noticeably higher transmission to wavelengths in the 600-700nm range, which renders a warmer image. Where the UVHD+ betters the SRBC is in suppression of glare, both veiling and general glare when glassing against the light. And while an 8 x 32 is no match for a larger 8 x 42 of equal quality, I found the performance of the UVHD+ to be excellent in summer twilight, where the Schott HT glass boosts light transmission in the 400-500nm range, which allows the darker adapted eye to perceive objects in the blue part of the visual spectrum that little bit better. I refer the reader to Holger Merlitz’sThe Binocular Handbook page 10 for details.
Conducting some observations of the bright summer star, Vega, the little Leica glass showed perfect collimation and quite a flat field. Only in the outer 20 per cent of the field or so could I detect a bit of field curvature which could be focused out, but there remained a small amount of astigmatism right at the field stops.
Though I did not do a side by side comparison, I would rate the optical quality of the Leica UVHD+ to be higher than the Zeiss SFL I tested some time ago. It just has a more relaxed view compared with the Zeiss, with the warmer colours and superb glare suppression, pulling it ahead. But this is bound to be rather a subjective impression.
One thing’s for certain though, the Leica UVHD + is much more in keeping with a pocket glass philosophy than either of the current Alpha glasses offered by Swarovski or Zeiss, as exemplified by the design of the NL Pure and SF 8 x 32 models, respectively. These are considerably larger in comparison, and so can’t really be considered to be in the same portability class, at least size-wise. In contrast, the little UVHD+ certainly can fit in an average coat pocket.
Value for Money?
The Leica UVHD+ 8 x 32 is an expensive piece of kit that’s for sure. But when I compare it to the optically excellent SRBC 8 x 42, which retails for one third of the price of the Leica, it gives me serious grounds for pause in recommending it, especially as an auxiliary travel glass. In addition, with the soon introduction of smaller 32 mm class of SRBCs offering the same excellent quality optics in ultra-flat fields fully twice the size of the Leica UVHD+ and at a fraction of its cost, it may render these smaller glasses by Zeiss, Swarovski and Leica all but obsolete. In the end, you vote with your wallet.
Dr Neil English is author of Choosing & Using Binoculars: A Guide for Stargazers, Birders and Outdoor Enthusiasts.
Title: The Privileged Planet (20th Anniversary Edition)
Published: 2004 & 2024
Authors: Guillermo Gonzalez & Jay W. Richards
Publisher: Regnery
434 pages
ISBN: 978-1-68451-702-2
Price: $35US
Is the Earth a unique abode of life or is life commonplace across the cosmos, with its myriad galaxies, stars and planets? Is the Earth a typical habitable planet or is it endowed with innumerable ‘just so’ features that has allowed life to flourish here for close on 4 billion years? Are we alone in the Universe?
These are big, blue sky questions for sure but the body of evidence hinting at the answers has stretched the ingenuity of our species to ever greater heights of technical sophistication, probing the cosmos at every conceivable scale in order to begin to glean the answers, and then only dimly.
Speculation regarding these questions has taken many twists and turns over the decades.
At the dawn of the 20th Century, most scientists would have argued that there is nothing special about the Earth and that the appearance of life was a scientific inevitability on many suitable worlds and across many epochs. The Universe they surmised, was infinitely old and large, so if life took hold here on Earth, why not on countless other worlds strewn across the heavens?
Some scientists even entertained the idea that our neighbouring planet Mars had vegetation as recently as the early 1950s, shored up by pseudosciences like Darwinian Evolution. In the 1980s, the popularised writings of planetary scientists like Carl Sagan prepped the general public for the expectation that we would one day discover other alien intelligences in our Milky Way galaxy or even beyond.
But In the last thirty years, we have made the most astonishing discoveries about the requirements for life that a new consensus is emerging; not only is the Universe fine tuned for life but the Earth appears to stand out like a proverbial sore thumb, even as we uncover tens of thousands of extrasolar planetary systems around nearby stars. In the pages of The Privileged Planet, astronomer Guillermo Gonzalez and philosopher Jay Richards, posit something even more profound: that the Earth is exquisitely designed for scientific discovery!
Drawing on an impressive range of scientific disciplines – cosmology, particle physics, planetary science, geology, astronomy and biology- the authors weave together a compelling argument that we live in an extraordinary place at an extraordinary time.
The Copernican Principle has been one of the unifying themes of modern science, which argues that there is nothing special about our place in the cosmos and our significance within it. Yet after presenting a wealth of new evidence from many scientific disciplines, the authors compellingly make the case that nearly everything about our planet, its unique composition, geology and hydrological cycle, our location within a very atypical solar system with a unique star at its centre, the presentation of perfect solar eclipses, and our place within the wider Milky Way Galaxy, puts humanity at an ideal place and time to discover the deep mysteries of the Universe. None of the great scientific achievements of our species, such as our discovery of the origin and expansion of the Universe, it’s great but finite age etc could have been achieved if we emerged earlier or later on the cosmic scene.
This enormous body of evidence is used to bolster a much more robust analysis of the so called Drake Equation, where estimates of the number of planets harbouring advanced technological civilisations in our galaxy is revised downwards to practically one; that is, our own world.
The book includes an extensive bibliography of scientific papers, and informed commentaries written by scholars in their respective fields. This deeply engaging and well-thought-out 2nd edition ought to appeal to a large cross-section of society from the religious, philosophic and scientific to the plane curious. Although the authors cover complex scientific concepts they are very well explained in ways a novice can understand. We may not be at the centre of the physical Universe but we are at the centre of its meaning and its purpose!
Highly Recommended!
Dr Neil English has a broad academic background in biochemistry, physics and astronomy. His highly acclaimed work, Chronicling the Golden Age of Astronomy, charts the four century history of visual astronomy, from Thomas Harriot to Sir Patrick Moore.
About a year and a half ago, a radically new series of high-performance binoculars hit the market: the Sky Rover Banner Clouds(SRBCs), packed full of state-of-the-art optical features delivering stunning levels of field performance. After reading some credible early reports, I pulled the trigger on the 8 x 42 model and reported my findings on the main binocular forums. For the first time, the SRBCs delivered premium performance at prices that were hitherto unheard of. Prior to the introduction of the SRBCs, you’d have to part with upwards of £2,000 to get anything approaching the optical performance of these new binoculars.
My review of the 8 x 42 went viral and despite vicious attacks by online trolls like Canip/Pinac, dries 1, Astronoob 76/ Binocollector and Vertigo/Conndomat, who hang around like a bad smell on either Cloudynights or the bino porn site, Birdforum, and desperately wanted them to fail mechanically, my 8 x 42 has worked flawlessly in all that time. Their psychology disturbs me:
We want you to buy an optically inferior instrument for substantially more money.
The Persistence of Memory!
Indeed, suffice it to say that I’ve used it more than anyone else. Indeed I can count on one hand the number of days out of the last 15 months where I’ve not used it for at least an hour every day. The Banner Clouds are robust instruments, built to study the Creation, designed for the great outdoors.
Let’s briefly revisit their features:
Double ED APO optics
Ultra-flat Field
Class-leading true fields(9.1degrees for the 8 x 42, for example)
High light transmission -92 per cent
Water repellant coatings on all outer lenses
A large, smooth and highly responsive focus wheel with no free play
Professionally edge-polished and phase corrected roof prisms showing minimal diffraction spiking on bright night lighting targets
Snugly-fitting objective covers and rain guards
A new choice of 2 types of removable eye cups to suit a wide range of facial profiles.
There is simply nothing to compete with these new alpha class binoculars except the best that Swarovski and Zeiss can currently manufacture, but all of this for a fifth of the price offered by the latter.
Seen in this light, the old ‘establishment’ alpha binoculars are highway robbery and terrible value for money. I’m simply not interested in using or promoting them to my readership. They need to reduce their prices, or look elsewhere for coin.
That’s just business.
I’ll be reporting back again in another 15 months or so, to give you another update. In the meantime, I pray that as many people as possible can get a chance to look through these revolutionary instruments.
So, there it is.
My original goal of finding the best binocular bargains for my readers has been successfully accomplished.
Job done!
Signing Off,
Sincerely,
Neil English, Author of Choosing and Using Binoculars.
When it comes to introducing the wonders of the night sky to beginners, it’s very hard to beat a small refractor. Praised for their crisp, high-contrast views and almost complete lack of maintenance, even absolute newcomers can quickly engage with the night sky. Over the last few years, the newly established company, Svbony, has brought to market very high quality astronomical gear at prices that were considered unthinkable only a few years ago. As a seasoned amateur astronomer, and experienced reviewer of telescopes, I have used Svbony eyepieces and other accessories with my own telescopes and can vouch for their great bang for buck.
Svbony reached out to me to request an honest review of their new entry-level telescope; the SV520 telescope: a 90mm air spaced F/8.9 achromatic refractor on a dedicated altazimuth mount with slow motion controls on both axes. I agreed to do so, and what follows is a fairly detailed overview of its quality and capabilities.
The SV520 telescope, mount and accessories arrived in a well packed double box. Though the instruction manual is clear and comprehensive, I found it easy to assemble the mount and attach the telescope in just a few minutes.
Let’s take a closer look at the telescope mount first. Having used a Vixen Porta II altazimuth mount for nearly 15 years, I was delighted to see that the SV520 came with a very similarly designed unit. It can accept a wide range of small telescopes using a regular dovetail plate. Slow motion controls provide smooth and precise tracking on both axes. The legs of the tripod seem to be made of stainless steel and can be extended to increase the overall height of the telescope for taller users. The legs can be securely locked in place using three large thumbscrews. The accessory tray screws onto the long vertical bar that mates the mount to the tripod legs.
The set up is quite stable with the telescope mounted. After giving it a hefty shake, I found the dampening times to last for just a few seconds, which is more than adequate even when using high power eyepieces. Incidentally the mount can accommodate loads of up to 5 kilos.
Two eyepieces are provided with the optical rube assembly: a 25mm and 10mm Kelner delivering powers of 32x and 80x, respectively. A decent mirror diagonal is also included for comfortable 90 degree viewing. It is not threaded to accept filters though.
The finder was arguably the biggest disappointment in the SV 520 package: a very plasticky 5 x 24mm specification with a singlet objective lens. As you can imagine, it produces very strong colour fringing owing to its short and stubby focal length. But I was able to align it easily with the main telescope and it did serve its purposes as a basic finder scope. Indeed as bad as it is, I think it’s still infinitely better than a generic red dot finder all too often seen on amateur scopes these days.
The SV520 comes with a removable plastic dew shield, which reveals the lens cell underneath. The focuser is a single-speed rack and pinion design, which moves very smoothly and has enough focus travel to use quite a lot of accessories including diagonals, or mounting photographic gear. It can also be rigidly locked in place if need be.
Optical Testing
To be honest, I was expecting good performance from this 90mm f8.9 achromat based on many years experience of long focus 80mm refractors I’ve owned and used over the years. The colour correction ought to be decent: as good in fact as a 4 inch F/10. The two eyepieces supplied with the telescope – a 25mm and 10mm Kellner – deliver powers of 32x and 80x, respectively. The 25x views were very nice. Good on the Moon, star clusters and the brighter nebulae etc. The 10mm Kellner also provided nice views of the Sun using a full-aperture white light solar filter. The slow motion controls on the mount allowed trouble free tracking with dampening times of just a few seconds.
But when I turned the telescope on the stars at 80x, I could immediately see that something was amiss. They were astigmatic. Defocusing the image of Capella both inside and outside focus confirmed this clearly. I was unable to get a good image of Jupiter and double stars were horrid. Clearly there was something wrong with the telescope. Taking out the star diagonal and peering down the tube showed the focuser rail was not parallel with the optical axis. I did attempt a ‘home fix’ of sorts by removing the dew shield, loosening the retainer ring holding the objective lenses in place and gently wiggling the lenses to see if they would settle into the cell better. Unfortunately, there was no improvement.
Disappointed, I dispatched the telescope to Es Reid, a professional optical engineer based in Cambridge, to see if he could get the optics working better. He confirmed the astigmatism and also noted the objective’s over correction. He added thicker lens spacers and got the focuser to move parallel with the optical tube. When I got the telescope back, I conducted more observations: first a star test at 180x under good seeing conditions. The astigmatism was gone and the intra- and extra-focal Airy disk looked a lot better. Turning the telescope on Jupiter, by now well past its best seasonal position in the sky, showed a much improved image: a few bands were clearly seen. Turning the scope onto Castor in Gemini showed the A and B components with excellent definition at 200x.
Upgrading the diagonal to a dielectric type and using better eyepieces significantly increased the quality of the images of both deep sky objects and higher resolution targets, like the Moon and double stars. Indeed I was now able to press the magnification to 200x or more with good results.
Conclusions: I understand that Svbony marketed this telescope for beginners, and to some degree, it performed quite well so long as the magnification was not pushed higher than 80x. But even beginners appreciate decent views of the Moon at high powers and for stars to look like pinpoints of light at magnifications above 100x. I don’t know if I received a bad sample or whether this was just a typical example, but Svbony are capable of much better than this. If you’re willing to live with low powers than this would be an OK telescope but, as it was presented to me, I cannot recommend it for those who wish to push the envelope a little to tease out powers of 200x or a little higher.
Neil English is author of Choosing and Using a Refracting Telescope.
Over the last few years I’ve watched spotting scopes grow in size. Just a few years back, birders and nature watchers routinely used 60-80mm scopes to study their targets at distance, but recently, a new breed of super big spotters have been released onto the sports optics market, with apertures of 95mm, 100mm and even a 115mm now being routinely employed by enthusiasts who can now enjoy greater light gathering power and higher resolution images. Big spotting scopes employing ordinary crown & flint glass suffer badly from chromatic aberration at higher powers, making them practically unusable at their highest magnification settings(60x or so), necessitating the need for extra low dispersion elements to reduce colour fringing, and increase image sharpness and contrast. But as the aperture increases whilst retaining the typical fast focal ratios(<F/6) required of spotting scopes, chromatic aberration becomes very aggressive indeed, requiring much more attention to detail. Many of these scopes have triplet objectives with one element employing fluorite crystal to stave off colour fringing around high-contrast targets. Fluorite is very expensive though, is very brittle and slightly water soluble, characteristics that reduce its durability in the long run. Another approach is to use two ED elements, similar to that employed by some fast refractor astrographs.
In this review, I wish to showcase a new 4-element, dual ED APO spotting scope by the Hong Kong-based company, Svbony, embodied in their new flagship line of premium spotting scopes, the SA401 series. Two models are available; the smaller 85mm and the 100mm showcased in this review. Furthermore, both retail for well under £1000.
First impressions:
Typical of Svbony, the SA401 100mm APO scope arrived in packaging I can only describe as immaculate. Double boxed, the instrument was sturdily positioned inside its white foam casing, together with various accessories, including a SV 402 1.25” eyepiece adapter, a 2 mega pixel SC001 imaging camera, and a black scope jacket to protect it from the elements. Let’s take a closer look at the instrument.
The magnesium alloy chassis of the SA401 100mm APO spotting scope is overlaid by a thick layer of forest green rubber armouring, with black extremities at the eyepiece and objective ends. The textured rubber single speed helical focuser is also finished in black. An attractive cherry-red ring positioned behind the retractable lens shade displays the essence of the SA401 design, employing two ED elements in its APO designation, and covering a magnification range of 25x to 75x.
The focused cone of light from the 4-element objective is reflected to the zoom eyepiece via a Porro prism using K9 optical glass(the optical equivalent of BK7) which is perfectly suitable for this F/5.6 instrument. In addition, K9 optical glass has a lower dispersion profile than BAK4, which helps a wider range of visible wavelengths to remain tightly focused before being magnified by the eyepiece.
Like their other spotting scopes, a large, round knob is located on the upper right of the chassis just ahead of the helical focuser. Once loosened, the built-in mounting bracket can be smoothly rotated through a full 360 degrees, which enables the user to achieve a comfortable viewing position irrespective of the location of the target.
The interior of the SA401 spotter is very clean and dust-free, as the photo below shows, with nicely machined baffles, and other blackened components to help reduce stray light and maximise image contrast.
Ergonomics:
The SA401 100mm APO 25x-75x tips the scales at 2.9kg, with the extra heft over other 100mm spotting scopes probably attributed to its 4-element objective. It feels really solid in the hand. Fit and finish are fantastic. The helical focuser moves smoothly and precisely allowing the user to bring any object beyond about 10m to a crystal clear focus.
The zoom eyepiece has plenty of eye relief. Testing with glasses on, I was able to access the entire field throughout the full magnification range of the instrument.
The zoom eyepiece can be removed from the instrument simply by unscrewing it. The user can then insert other eyepieces or the supplied SC001 imaging camera, by means of the SV406 adapter (also supplied), as shown in the photographs below:
For most of my initial testing, I mounted the SA401 on my trusty Vixen Porta II altazimuth mount via a small dovetail plate seen attached to the instrument in the second photo above. This mount has slow motion controls on both axes, allowing me to quickly centre a target or track it. For more portable work away from my home I elected to use the lighter weight SV402 mount with its fluid panning head. More on this later.
That’s a reassuring result, as the whole point of using a large spotting scope like this is to avail of its additional light gathering power, especially in low light situations.
Bright Light Test: Not all people who buy and play around with spotting scopes will use them for nature studies. Some folk who live in high rise apartments like to get good views of the town or city in which they live, whether by day or by night. A spotting scope showing strong internal reflections from bright city lights would be off putting. To test this, I turned the SA401 on some bright street lights at various distances up to 100 yards away. I’m happy to report that there was very minimal reflections seen and only on the very brightest sources. This would be a good instrument to enjoy cityscapes after dark.
Optical Impressions:
Arriving late in the afternoon on a dull winter’s day, I aimed it at some trees about 100 yards in the distance. Racking the zoom eyepiece throughout its 25x to 75x range, I was able to get a very sharp, crisp and bright image with excellent contrast at all magnifications. Edge-to-edge sharpness appeared excellent in my test unit. Colours were natural: not too warm or cold. The apparent field of view(AFOV) became quite noticeably wider as I moved up in magnification though. Moving back to 25x I felt the field was a little narrower than I expected based on my experience with other zoom eyepieces. Looking closely at some branches against a grey sky showed that the instrument displayed very minimal colour fringing at the 75x setting. I could immediately tell this was a noticeable step up in colour correction from the SA405 85mm scope(an ED triplet) I reviewed a couple of years ago. Some of this residual CA was coming from the eyepiece for sure. Over the next few days, I took a series of images with my IPhone just handheld to the eyepiece set at 75x to give the reader an impression of the degree of colour correction evident in the scope in various lighting conditions, drawing on the excellent work of Roger Vine who reviewed the Zeiss Harpia 95mm spotting scope. Let’s take a closer look:
The above image zoomed in to look at the aerial:
And tree branches against a dull grey sky:
In the next two images, I present a view of a Rook perched high in a tree with the winter Sun behind me, followed by another Rook against a dull grey sky:
In one final test for chromatic aberration, I inserted the SC001 digital imaging camera into the optical train and pointed the properly acclimated scope at a waxing gibbous Moon. Here is a single shot I obtained:
Commentary on the Images
I hope the reader who carefully examines the images, which have not been processed in any significant way, will conclude, as I have, that colour fringing in the SA401 100mm spotting scope is extremely low or even insignificant. This residual secondary spectrum could easily be removed post processing of course. Reflecting on Mr Vine’s comments on Zeiss’ flagship spotting scope and his posted images, I would agree that even this very sophisticated (with a price tag to match!), shows significant lateral colour, even more I’d say, than the SA401 tested here. Vine also makes the point that observing a jet black Crow against a uniform grey background sky will show colour fringing even on a scope as sophisticated as the Zeiss Harpia. The reason is that high-end spotting scopes have far more complicated optical designs than regular ‘apochromatic’ astronomical refractors, and it shows when eliminating the last vestige of false colour in the image. What’s more, optical testing of high-end spotting scopes show they fall below that of high quality astronomical refractors, but work fine within the magnification range over which they were designed.
Vine likens the view through the Harpia to a Televue 85: a simple ED doublet, at the same magnification. I would add that this is very likely to be the case on any high end spotting scope advertised as ‘APO.’ If you want better apochromatic performance at powers beyond 60x, you’re going to have to move to a moderate focal length (>F/6) astronomical triplet ED refractor and put up with the world the wrong way round(read left-right reversed).
The reader will also take note of the edge performance of the SA401 spotting scope, as evidenced by the image of the trees, showing the sharpness right up to the field stops. That’s an impressive result, in my opinion, and quite in keeping with my initial visual report. The SA401 does not utilise a field flattener but its excellent edge sharpness is probably down to its smaller true field of view(1.77 degrees).
Further Optical Tests:
To further substantiate these comments I set up my Skywatcher Evostar ED 80- an 80mm F/7.5 FPL53 ED doublet APO using Schott optical glass – with the SA401 spotting scope to compare their colour correction on a high contrast target.The little Evostar is a proven standard in apochromatic performance. It shows only a trace of false colour on the highest contrast targets.
I took a handheld image with my IPhone at 75x on a telephone wire about 30 yards in dull, overcast conditions, at about 30m in the distance. Here are the results. The first image is taken through the Evostar 80ED and the second was shot with the SA401. The sky brightened just a little while taking the Evostar 80 ED image.
You can see that the colour correction is very comparable in both instruments. The decently slow F ratio of the ED doublet ensures a well corrected optic. Visually, I felt the Evostar ED had slightly better contrast and colour correction compared with the bigger SA401, though I did notice that the image was significantly brighter in the latter. The reader will note the left-right reversed image from the Evostar.
Under the Stars:
The collimation of the SA401 100mm spotting scope was perfect. I used the SC001 imager to get an image of the intra-focal Fraunhofer diffraction pattern of the bright star Capella, with limited results, as it’s not designed to take high resolution astronomical images. Nevertheless, you can see that the pattern is perfectly round, indicative of the proper squaring on of all the components in the optical train. A few of the outer diffraction rings are also in evidence:
With three outer planets on the sky at the time of writing I was keen to see how they appeared in the SA401. Saturn showed a beautiful yellow globe with the rings seen almost edge on at 75x. Mighty Jupiter, now exceptionally well positioned in the night sky at my northerly latitude, was magnificent at 75x. The creamy-white oblate sphere was tack sharp with no false colour, the planet crisscrossed by numerous belts and zones. I enjoyed several satellite eclipses over a period of weeks and I was impressed to be able to see the famous Great Red Spot at this relatively low power. Fiery Red Mars rising later in the constellation of Cancer, showed a tiny, crisp orange disk with no chromatic aberration that I could make out. The views I enjoyed at 75x inspired me to crank up the power to get a closer look.
As mentioned earlier, the SA401 is capable of accepting 1.25” eyepieces, but not all those I tested were able to come to focus at infinity. While simple short focal length Plossls and orthoscopics worked superbly, one of my absolute favourites, like the exceptional Svbony SV215 3-8mm planetary zoom, did not focus at infinity. By unscrewing the lenses from my 2x and 3x Barlow lenses and placing them ahead of these eyepieces, I could boost the magnification further(up to 200x). Another winning combination was inserting these amplifying lenses ahead of the SV191 7.2-21.6mm zoom to give a useful range of magnifications.
Perhaps the best way to glean higher powers from the SA401 is to use Svbony’s Gold Series 6mm wide angle eyepiece with its 66 degree AFOV. It sports very generous eye relief – far more than any short focal length Plossl – generating a power of 93x. What’s more, when a 1.6x Barlow is screwed into the nose of this eyepiece, it delivers a power of 148x – plenty high enough for most any application. And yes, the configuration focuses at infinity!
The 6mm Gold Series also has a large and comfortable eye lens for easy eye placement.
Taking advantage of exceptional seeing conditions during the second week of December, when a huge high-pressure bubble over Scotland brought calm but gloriously clear sub-zero temperatures, I turned the instrument on these planets once again. Saturn at 150x looked even more magnificent with its largest satellite, Titan, easy to see. Jupiter showed very nice details at 139x – swirls, spots and festoons, racing their way across the planet as it rotated. The instrument stubbornly refused to show any significant secondary spectrum. On one night, I watched as a Galilean satellite appear as a tiny ‘pimple’ on the limb of the planet, growing larger as it rounded mighty Jove, before ‘pinching off’ to join the other moons in orbit. Wonderful! In the wee small hours of a freezing December night, I cranked the magnification up to 180x to take a closer look at Mars. Though the ruddy Martian disk remained small, I was clearly able to make out the Syrtis Major and a prominent northern polar ice cap. A word of advice would come in handy here. The complex optical design of this spotting scope needs some time to acclimate. Taking it out on a whim from a warm indoor environment to observe the planets at these high powers will likely disappoint. I recommend a good hour of prior acclimation to get the best out of this telescope.
The SA401 100mm spotting scope shows stars as beautiful pinpoints with no chromatic halos around the brightest luminaries. While I’ve been blown away with the views served up by a high-quality 15 x 70 binocular, the view of the Pleiades through the SA401 on a dark, moonless night, was quite simply a show stopper! The beautiful asterism filled the low-power field at 25x, with its constituent blue- white stars shining gloriously. I could even make out some hints of the reflection nebula around Merope. And while my main telescopes are all optimised Newtonians, the view through the SA401 brought back fond memories from my small refractor days, with its crisp, high-contrast views.
As a double star specialist, I was keen to see how the SA401 fared on a variety of these targets. Choosing a power of about 150x, I managed excellent splits of Castor A & B, Epsilon 1 & 2 Lyrae, Polaris A & B, and the spectacular triple system, Beta Monocerotis. Rigel proved more elusive, but on a night of very good seeing, I managed a convincing sighting of its faint close-in companion. I could have visited many more but star hopping is a lot more challenging without a finder scope. Sighting along the side of the tube just has its limits!
All in all, the SA401 proved to be an impressive performer under the stars. It would really benefit from having a simple finder though especially for astronomical applications or when using high powers during daylight. Perhaps a Rigel Quikfinder or some such?
Field Craft:
A large, high-quality spotting scope like the SA401 deserves a decent mount for mobile terrestrial observations. I was looking for a tripod light enough to carry on foot, but strong enough to accommodate the sizeable weight of this big 100mm instrument. I took a punt on Svbony’s SA402 tripod which has a number of attractive features, including its light weight(2.2 kilos) a hydraulic gimbal and large pan handle for easy manoeuvres both in azimuth and altitude.
It comes with a quick-release bracket for rapid and easy mounting and dismounting of the spotting scope. The strong, extendable 30mm-diameter aluminium legs reach a height of about 65 inches: perfect for my standing observations and imaging applications. Fully retracted, it stands just 27 inches above the level ground.
The sturdy head can support weights up to 6 kilos. One other nice feature of the SA402 mount is the ability to lock the leg spreaders in place. The base of the legs also have decent rubber pads to add extra grip. Though I would not recommend the SA402 for astronomical observations, owing to its lack of slow motion, fine controls, it proved ideal for using the scope during the day.
The black neoprene jacket fits snugly around the telescope and provides extra protection of the optics against the elements.
Placing the scope on the SV402 mount, it made sense to swap out the zoom eyepiece on the SA401 for the SV191 7.2-21.6mm using the supplied adapter as the same adapter was used to mount the SC001 imager. Carrying the entire set up on my shoulders, I walked a half a mile up to my local pond to capture some images of the wildlife out on the water.
All the images were shot on a dull,overcast mid-January day with some light rain showers complicating matters. Nevertheless, the SA401 is weather sealed against the elements and coped well under the circumstances. For scale, all the subjects captured were located at about 100m in the distance. The images all underwent some basic IPhone processing after capture.
Conclusions & Recommendations:
The SA401 25-75x 100mm APO is a powerful and versatile spotting scope with excellent, pin sharp optics and robust ergonomics. As well as its optimised daylight performance, it can also be used to explore the night sky. Chromatic aberration is very low and edge-of-field performance impressive. To get anything better, I suspect you’d have to spend at least twice as much again. Svbony offer these scopes in a variety of packages, with the tripod, SC001 imager, or DSLR adapter depending on your requirements.
Finally, it’ll pay the reader to have a look at two other reviews I found on the SA401 for comparison:
Review A: Taken Directly from Amazon
This is my first spotting scope outside the alpha scopes from Zeiss, Swarovski and Leica, I have always bought secondhand because I couldn’t afford them new and wanting a 100mm aperture there was no Way I could afford any of the three alpha brands I have already have the Swarovski 80hd and zeiss diascope 85fl both 15 years old,After reading Neil English review on the svbony sa405 spotting scope and I already have many of svbony eyepieces and their 503 Telescope I decided on their top of the range 100mm sa401 spotting This is stunning spotting scope with performance way above its price range and easily outperforms many 80mm ed spotting scopes,it is brighter than my swarovski and Zeiss diascope. The only 100mm I had used was the 100mm celestron Regal ed and the sybony is clearly superior by quite a margin. This sybony 100 ED easily outperform many 80mm ed scopes,I have tried many mid price spotting scopes and always been disappointed but this svbony is the exception it absolutely blew me away and I don’t get impressed easily. Now for the negative:the eyepiece is only average and shows some chromatic aberration but this is only due to the eyepiece and and not the spotting scope,I have to modify it to accept astronomy eyepieces and I can honestly say it outperform the Swarovski/Zeiss although I have an adapter for the Zeiss to use astronomy eyepieces the sybony still beats it I would like to compare it to the lasted Zeiss diascope but it’s priced beyond my reach. I have updated my review from 4 stars to 5 stars due to the focus being tight to turn and the average eyepiece but the focus have loosen up and I can use astronomy eyepiece. To sum up this should set the standard for spotting scopes up to £1,400 those photos were with the pentax 12mm astro eyepiece fitted to the Svbony SA401 100mm spotting scope
I’ve been experimenting with a few more eyepieces that can be coupled to the instrument. Taking a punt on an ANGELEYES branded 22mm ultra wide angle, I was really impressed with the much wider field of view delivered by this 1.25” eyepiece. On paper this 70 degree AFOV ought to deliver a power of 25x in a 2.8 degree field but the limited diameter of the eyepiece port on the spotting scope reduced this field to somewhere nearer 2.3 degrees. Still, this is a huge improvement over using the dedicated zoom. I use it mostly as a rich field eyepiece to enjoy the glories of the night sky.
In addition I’ve found the red-label Svbony 15mm eyepiece with its 68 degree AFOV to be an excellent, economical mid power eyepiece delivering a magnification of 37x in a great 1.8 degree field.
I believe both these eyepieces will greatly enhance the viewing experience with the beautiful SA401 100mm APO spotter. Check them out if you get a chance!
Dr Neil English explores many more bargains in his latest book, Choosing & Using Binoculars: a Guide for Stargazers, Birders and Outdoor Enthusiasts.
