A Work Commenced December 9 2024.

Product: Svbony SA401 25x-75x 100 APO

Country of Manufacture: China

Clear Aperture: 100mm

Armouring: Forest Green Rubber

Magnification Range: 25x-75x

Field of View: 1.77 degrees @ 25x -0.92degrees @ 75x

Focal Length: 556.2mm

Focal Ratio: 5.6

Focuser: Single Speed, Helical

Coatings: Fully Multicoated

Objective Design: 4-Element Double ED APO

Prism Type: K9 Porro

Exit Pupil: 4mm@ 25x, 1.3mm@ 75x

Ability to use Interchangeable 1.25” Eyepieces:Yes

1.25” Eyepiece Adaptor: Yes

Waterproof: Yes IPX7

Nitrogen Purged: Yes

Weight: 2.9kg

Length: 458mm

Accessories: 1.25” eyepiece adaptor, SC001 imaging camera, scope protective jacket, IPhone adaptor, instruction manual, lens cleaning cloth

Price(UK): £779.99

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 are 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. Thankfully, there are other, less costly ways of achieving much the same or better results, such as using two lower-grade ED elements in the objective design. Typically, these bigger triplet spotting scopes command prices upwards of £1400, while top European brands will usually set you back twice as much or more again. 

In this review, I wish to showcase a new 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. 

To be Continued…….

De Fideli.

A Work Commenced May 26 2023

Preamble

In Part I of my review, I described the general optical and ergonomic features of the Svbony SA405 20x-60x 85mm ED spotting scope. In Part II I would like to reveal more about its ability to incorporate different eyepieces as well as its imaging capabilities.

The zoom eyepiece accompanying the SA405 is removed simply by rotating the rubber sleeve at the base of the eyepiece housing anticlockwise which loosens the grip on the zoom, allowing it to slide up and out of the ocular interface. The photo below shows the rectangular face of the Porro prism just beneath an anti-reflection-coated optical flat situated immediately above it, which effectively seals off the optics from the ambient environment.

The nicely designed stops prevent any direct contact between the inserted eyepiece and the flat so there’s no chance of it cracking or scratching the glass. After inserting the new 1.25” eyepiece it can be tightened via a helical mechanism by rotating the rubber sleeve clockwise until its tightly fixed in place.

In the next series of photos, I‘ve attached a Sirius Plossl 7.5mm and a Celestron X-Cel 25mm- to the scope.

But by far the most versatile eyepiece I found for this scope is the Svbony SV 191 7.2-21.6mm zoom eyepiece offering a magnification range between 22.3x to 67x, so a modest gain in magnification over the original 20x- 60x. More on this zoom later.

Determining the Maximum Field of View Available to Ordinary Eyepieces using the SA405

The provided zoom serves up a maximum field of view of just under 2 angular degrees. I determined to establish whether I could expand this field by using fixed focal length eyepieces. In this capacity, I set up some experiments using both a Celestron X-Cel LX 25mm with a 60 degree AFOV. In theory this should have served up a true field of 3.1 angular degrees. In addition I tested a 32mm Skywatcher Plossl eyepiece which should serve up a field of 3.45 angular degrees(52 degrees AFOV). However, the effects of vignetting would likely come into play, restricting the true size of the fields generated by these long focal length eyepieces.

Accordingly, I measured the fields of these eyepieces by conducting a star drift timing test. In the wee small hours of a late May morning, under decidedly twilit conditions, I centred the bright star Altair with a declination of +8.87 degrees, so just above the celestial equator(well within the +/- 20 degrees required for accurate results), I timed how long it took for the star to reach the field stop and used these values to calculate the true field( times were actually  doubled). The results I got were as follows:

25mm Celestron X-Cel LX – 3.05 degrees

32mm Skywatcher Plossl- 2.93 degrees

Comments: The Celestron eyepiece served up a field size in good agreement with its specifications. The Skywatcher, as expected, vignetted the field, delivering a field size pretty much indistinguishable from the shorter focal length Celestron.  Since there is no material advantage to having a lower magnification with the same field size, the Celestron is the better eyepiece for dedicated low-power widefield viewing.

Experiences with the Svbony SV 191 7.2-21.6mm Zoom Eyepiece

The SV 191 7.2-21.6mm zoom is a very nicely designed eyepiece. The zoom motion is extremely smooth and continuously variable. It has twist up eyecups with excellent eye relief. Unlike the 20x-60x zoom that comes as standard with the SA405, the SV 191 can be used comfortably with eyeglasses throughout the entire magnification range. Another really neat feature of this zoom eyepiece is that it’s parfocal – or very nearly so. That means that only very minor tweaking is necessary if you decide to change magnification. Moreover, the SV 191 zoom tips the scales about 100g lighter than the supplied zoom, reducing the overall weight of the scope – surely a good thing when portability is to be considered.

Optically it’s very nice too. The image remains tack sharp all the way through the full magnification range. Contrast is very impressive with accurate colours coming through. The SA405 remains very well corrected for false colour using this eyepiece, as the image below illustrates.

On the evening of May 27, I took a simple handheld shot of the first quarter Moon at the 67x setting through my iphone7. I hope you’ll agree the image generated shows excellent details along the terminator with the magnificent Apennine Mountain range visible near the top of the image.

Zoom eyepieces have really come along way over the last decade or so. Having owned and enjoyed the Baader 8-24mm Hyperion zoom for astronomical applications, this nifty Svbony eyepiece delivers equally good images in my opinion but at a fraction of the former’s retail price. I picked this up for £58.99 on Amazon UK.

I took the opportunity to do some more star testing with this new eyepiece, taking advantage of its higher maximum power over the supplied zoom. Conducting several tests over a few nights of good, stable seeing, I’m confident to declare that its figure is a solid 1/6 wave P-V under-correction; an excellent result.

The SV 191 also afforded an excellent opportunity to see the effects of boosting magnification while observing a star field.

Starting at the 21.6mm setting, the sky is quite bright with only the brighter stars being visible. Racking the magnification upward allowed me to immediately see much fainter stars in the same field, as the sky became progressively darker; an easy and compelling way to see the dramatic effects of magnifying power on a telescopic image.

Higher Power Experiments and the Grey Heron that Came to Nest

I’ve tried using a few Barlow lenses to boost the power of the spotting scope in the hope that it can be called into play for higher power astronomical observing. The results I’ve achieved thus far are mixed. For example, by unscrewing a regular 2x Barlow lens housing and mating it to the either the SV 191 or a 10mm and 7.5mm Plossl eyepiece, I can get rather good images but only on nearby objects. The arrangement doesn’t come to focus on targets beyond abut 40 metres or so. Still, what I’ve seen thus far encourages me. There is more chromatic aberration in evidence, as expected, but the images remain sharp and well defined. I have ordered up a decent quality 4mm Plossl eyepiece that I hope to use to boost the magnification to 121x, thereby bypassing the need for a Barlow. I’ll report back on my findings once I’ve conducted those tests.

Over the last few weeks I’ve come to discover that there’s a Grey Heron nest within a stone’s throw of my back door. I was first alerted to this not by seeing anything, but by hearing it. One evening, as the dusk was darkening, I was setting up my 130mm Newtonian telescope for a night of double star observing. The air was filled with the sound of Rooks, many of which roost in the copse beyond my back garden, but every now and then, I heard an entirely different sound; a sound I had heard before – the sound of a Grey Heron!

It was coming from the trees immediately to the left of my house, but judging by how loud it was, it couldn’t have been more than a few tens of metres away. On another evening, I was coming back from a walk with my binocular, when I first sighted something unusual as I made my way through the swing park just across from my house. Something was fluttering in the conifer trees to the left of my back garden which caught my eye, but for a few days I was unable to make a definite ID. Finally one evening, I saw something that enthralled me: an adult Grey Heron flew over the roosting Rooks, creating one hell of a kerfuffle, as it landed in a medium-height conifer where I had previously pinpointed the sounds! This was the hard evidence I had sought! Grey Herons had indeed made a nest in these trees!

To say I was surprised would be an understatement!

I mean, Grey Herons are notoriously timorous, flying away at the mere sight of anyone coming within a hundred yards of them. At least that’s what I had experienced from a few years birding at one of my local patches up at Culcreuch Pond. Boy was I surprised to discover they were roosting in some trees just beyond my garden! But as I started to converse with some more knowledgeable neighbours of mine, they confirmed that these birds do indeed choose conifers to nest in.

On the sunny afternoon of Sunday, May 28, I picked up the scope astride the photographic tripod and made my way across to the swing park, setting up the instrument along a line of sight to the nest, some 150 yards in the distance. Zooming in using the SV 191 eyepiece I was delighted to see a youngster concealed among the branches. Racking up the magnification to 67x, I waited to get a better view, and my patience paid off, as the young Heron poked its long, slender neck upwards to have a look around. It was amazing! I ran down to get my wife and a next-door neighbour also joined in to have a gander at the sight. Indeed, truth be told, my wife didn’t quite believe me when I first disclosed my suspicions, but, as they say, seeing is believing! lol

I’m now thinking about how I can best image this bird before it flies the nest!

Using the Svbony SC001 Imaging Camera

Svbony also sent me their latest imaging camera, the SC001, with the SA405 spotting scope. This neat little device has a 2 megapixel chip, with a screw-on aerial that creates a WIFI hot spot which links to the SC001 camera App that can be downloaded free from the App store.

It’s dead easy to use. Simply insert the camera into the eyepiece interface, turn on the camera and open the App. The SC001 allows you to take single images or record video. The SC001 also has a built-in UV-IR blocking filter.

After playing around with the instrument for a few minutes, I set up the scope at the spot in the swing park where I had been scoping the young Heron the previous evening. I made sure to bring the zoom eyepiece to get my bearings, as the SC001 produces pictures with an image scale equivalent to the 60x zoom setting. Once the camera is switched on and the aerial attached you open the App and the camera begins delivering live images to your phone. Simple. The stored images must be downloaded to your photo gallery in order to get the full resolution details.

As luck would have it, the young Heron was active in the nest this evening, and after focusing carefully, I began taking a series of shots, three of which are shown below. All the images of the Heron(s) were taken on a warm sunny evening making imaging at long distance more challenging.

The reader will note that no image processing was conducted.

What an impressive piece of kit! So easy to use, small and easy to carry about!

As soon as it got reasonably dark on Monday May 29, I ventured out again with the SA405 spotting scope with the SC001 imager. Here’s a shot I took of the waxing gibbous Moon. The reader will note that this was the raw image delivered by the camera with zero processing.

As you can see the camera did a great job picking up those finer lunar details. The image scale is more like 75x though and not 60x as originally stated. I also note the amount of colour fringing is even less using the SC001 imaging camera, indicative that at least some of the already minimal amount of colour fringing was attributed to the use of the SV 191 eyepiece. Indeed, I was able to verify that the same level of colour fringing was captured using the supplied 20x -60x zoom eyepiece.

Conclusions & Recommendations

The SA405 is an excellent, high performance spotting scope, offering crisp, high-contrast images with minimal colour fringing consonant with its triplet ED billing. It can be used for purely visual work but also works well with modern Digi scoping methods, and when coupled to the SC001 imaging camera, it serves up excellent images with even better colour correction than that observed visually. The SC001 camera is a brilliantly designed device that can be used virtually anywhere, as it creates a WIFI hotspot with your mobile phone. and is small and lightweight for easy transport in the field. I would heartily recommend these instruments to both novice and advanced birders and naturalists who wish to get the very best bang-for-buck for their hard-earned cash. That’s got to be good news in these hard economic times we find ourselves in.

Dr Neil English’s new book, Choosing & Using Binoculars: A Guide for Stargazers, Birders and Outdoor Enthusiasts, will be published later this year.

24/6/23 Postscriptum: Svbony has compiled a short YouTube video presentation of some of the Images I captured through the SA405 and SC001 Imaging Camera!

De Fideli.

A Work Commenced May 3 2023

Preamble

Product: Svbony SA405 20x-60x 85mm ED Spotting Scope

Place of Manufacture: Hong Kong

Clear Aperture: 85mm

Focal Length: 482.6mm

Focal Ratio: F/5.7

Objective Type: ED Triplet

ED Glass: Yes

Interchangeable 1.25″ Eyepieces: Yes

Field of View: 1.92 -0.93 degrees

Eye Relief: 19.5-18mm

Eyepiece Diameter: 28mm

Eyepiece Design: 10pieces/7 Groups

Armouring: Army Green Rubber

Prism Type: K9 Porro

Coatings: Fully Multicoated

Retractable Dew Shield: Yes

Focuser Type: Single Speed Helical

Rotatable Tube: Yes, 360 degrees

Waterproof: Yes (IPX6)

Nitrogen Purged: Yes

Close Focus: 12 m advertised, 11.06m measured

Dimensions: 43 x 17.3 x 10.3cm

Weight: 2.1 kilos

Accessories: Soft Protective carry case/weather shield, rubber objective and eyepiece covers, instruction manual, microfibre lens cleaning cloth

Warranty: 1 Year

Retail Price: $589.99

Hong Kong-based technology company Svbony has been on my radar ever since I test drove their excellent SV 202 ED binoculars. These very economically priced instruments are packed full of advanced features that have delighted many thousands of hobbyists around the world with their excellent build quality and great optical performance. Indeed, the SV202 8 x 42 ED is the only full-size roof prism I now use. Svbony are even better known for their astronomy products, from eyepieces to high-quality ED refractors, where they have garnered an excellent reputation for producing high quality products at prices that won’t break the bank.

In a previous review, I showcased their high-quality mini spotting scope, the SV410 9x-27x HD spotting scope (see the Preamble link above) and was very impressed with its optical and ergonomic qualities. While the SV409 serves as a great ultraportable scope, it lacks the higher magnification and greater light grasp of larger aperture spotting scopes mostly employed by birders. These limitations got me curious about test driving a substantially more powerful spotting scope, so I contacted Svbony enquiring about their new high-performance SA405 20x-60x 85mm ED spotting and they agreed to lend me a unit for testing and evaluation.

First Impressions

The instrument arrived extremely well packaged inside a medium-sized, padded box. As well as receiving the spotting scope, I also received a very nicely made soft padded case that can also serve as a protective neoprene sleeve for observing in adverse weather conditions. A comprehensive manual explains all the features of the scope and how best to get it set up for use.

The scope itself is extremely well built and very handsomely presented, tipping the scales at just over 2 kilograms. Covered in a tough, textured army green rubber, it’s beautifully streamlined and easy to hand hold. The zoom eyepiece delivers a continuously variable magnification range from 20x to 60x and moves smoothly throughout its travel. It has excellent twist-up eyecups that click into place firmly. The eye lens is pleasingly large at 28mm making eye placement over the scope easy and intuitive.

The interior of the instrument is immaculate with no dust, residue and nicely machined components.  The tough rubber objective and eyepiece covers are very tightly fitting to keep the optics safe when not in use. These are a far cry from the cheap plastic covers I’ve seen on other spotting scopes on the market.

The single-speed helical focuser is a significant improvement over the smaller SV 409 mini spotter I tested a couple of years back. It’s much easier to turn – surely a good thing, especially at the higher powers where precise focus is an absolute necessity.

The mounting ring is rotatable through 360 degrees and is very nicely indexed which you can hear as it clicks into its various positions that can be maintained by tightening the thumbscrew. This allows the user to adjust the position of the eyepiece so that you can achieve your most comfortable viewing position.

The large 80mm triplet objective has very evenly applied multi-coatings, as do the eyepiece lenses, which have a pale greenish tint in broad daylight.

The retractable dew shield slides smoothly and affords excellent protection from stray light and glare and by helping to keep the objective lens elements dry when used in rainy weather. Its matt black colour complements the army green a rubber armouring of the scope beautifully.

The K9 Porro prism used to direct the light into the eyepiece is good match to the optical specification of the instrument. K9 is optically equivalent to BK7, and while not as good as BaK4, is perfectly adequate as the focal ratio of this scope is 5.7, well above the f/4 threshold under which BK7 or its equivalents show their limitations. K9, like BK7 has a lower dispersion than BaK4 too and so should help control chromatic aberration that little bit better.

The SA405 spotting scope comes with a built-in mounting bracket to enable it to be easily attached to photographic tripods. For more precise manoeuvring of the scope, I also attached a small dovetail plate so that I could mount it on my trusty Vixen Porta II altazimuth mount with slow motion controls.

The unit is waterproof (IPX6 rated) o ring sealed and purged with dry nitrogen gas to prevent internal fogging in cold weather. I tested this out by exposing the instrument to very cold, sub-zero temperatures for a couple of hours before bringing it into a warm indoor environment. The outermost lenses fogged up, as expected, but as soon as it was dispersed, I could see that the interior remained dry and fog free. Good job Svbony!

All in all, I came away extremely impressed with the instrument’s solid build quality and nicely thought-out ergonomic features.

Mountng Options

I elected to do all my testing using a strong but lightweight photographic tripod as well as a heavy duty Vixen Porta II altazimuth mount equipped with slow motion controls on both axes The latter was my preferred set up for use in my back garden and also for astronomical use. Here’s the scope mounted on my portable photographic tripod.

And here is the instrument on the Vixen Porta II altazimuth mount with slow motion controls.

Optical Testing

Before providing a general overview of the optical performance of the SA405 20x-60x ED, my first test was to confirm that it had a low dispersion element to cut colour fringing to a minimum. Accordingly, I mounted my non-ED Pentax 20x 60 PCF binocular offering a broadly similar field of view of just over 2 angular degrees and compared it to the view through Svbony spotting scope set at 20x.Two high contrast targets were selected; a telephone pole and some tree branches set against a bright overcast sky. The differences were quite striking: the Pentax easily showed obvious colour fringing on these high-contrast targets both on and off axis, while the SA405 spotting scope delivered far less on the same subjects. I could see none at all on axis and only a trace of lateral colour in the outer 20 per cent of the field. This test was very compelling, clearly showing the drastically reduced colour fringing in the Svbony spotting scope.

My next battery of tests took place after dark, where I trained the scope on the bright star Vega, cranking up the power to 60x. Before any such testing was conducted, I left the instrument cool off in a dry unheated outhouse for about an hour to give the optical elements time to acclimate to the cool night air. My experience with triplet refractors inspired me to issue a more detailed explanation of this phenomenon in my book, Classic Telescopes, specifically in the chapter entitled, “Why the Classical Refractor produces the most Stable Images.”

In focus Vega displayed a perfectly round Airy disk with a faint first diffraction ring. Defocusing the star produced a beautiful, smooth Fraunhofer diffraction pattern of concentric rings indicating the proper squaring on of all the elements in the optical train. Racking the star inside and outside focus revealed a touch of spherical under-correction based on the simulated images presented in Richard Suiter’s Star Testing Astronomical Telescopes. I would estimate the figure to be about 1/5 to 1/6 wave PV, certainly better than the Rayleigh Criterion of ¼ wave PV. The same tests showed the merest trace of colour fringing when Vega was at best focus. All in all, these were very good results indicating no significant optical issues.

Daylight Impressions

The Svbony SA405 produces crisp, high-contrast images throughout its magnification range. The single speed focuser is perfectly adequate for finding precise focus since it moves very smoothly and accurately, snapping to focus with no ambiguity, despite the instrument having a very shallow focus depth. Personally, I find dual speed focusers on spotting scopes to be overly fiddly. It just increases the number of knobs you have to play with, complicating the task of focusing. The scope is not parfocal though, meaning you have to refocus every time you change magnification.

Aiming at a series of tiles on a roof at 20x, the image remains tack sharp nearly all the way across the field, with only slight softening occurring in the outer 10 per cent of the field. Cranking the magnification up to 60x, the same tests showed the image to be completely sharp from edge to edge. Below about 45x, high contrast targets show little or no fringing in the centre of the field even under poor lighting conditions. As the power is increased to 60x, I could detect some lateral chromatic aberration in the outer part of the field of high contrast targets, but it remained very well controlled in the central part of the image.  This is par for the course for any high-end spotting scope and in this capacity the SA405 handled the targets very well indeed. What’s more, it’s difficult to know whether this residual fringing is attributed to the eyepiece or the objective.

Close focus was found to be just over 11m, a little closer than the advertised 12m. Though the scope has twist up eyecups, I elected not to adjust them, leaving them fully retracted.  At magnifications up to 40x the entire field of view can be accessed with glasses on. Moving from 40x to 60x, the full field becomes progressively more difficult to see and at 60x, I could not see the entire field using my eye glasses. Luckily, I don’t normally view with spectacles, so this restriction was of little consequence to me.

More Nightime Testing

Turning the Svbony SA405 spotting scope onto a bright sodium streetlamp after dark produced excellent results. I could only detect a single, very weak internal reflection while the image of the lamp remained razor sharp with no haze or diffused light around the target. “This will be a great Moongazing scope,” I wrote in my journal. Over the following few evenings, I enjoyed clear skies allowing me to put this conjecture to the test my making some observations of the crescent and first quarter Moon with the instrument astride my Vixen Porta II altazimuth mount. The view at 20x was very impressive; very sharp, lovely contrast and only the merest trace of fringing seen when the Moon was moved to the edge of the field. I experienced the same results on the Moon as I did when I examined the tiles in the daytime; it remained pleasingly sharp across most of the field but lost some definition near the field stops. Since most of this distortion could be focused out, I deduced that the main culprit was mild field curvature. The Earthshine on the April crescent Moon was awesome to behold; always a beautiful sight with high quality optical instruments.

Cranking up the magnification to 60x I was delighted to see a wealth of high-resolution details as the Moon phase grew from a slender crescent to first quarter.  Crater fields in the southern lunar highlands stood out starkly, and especially along the day-night terminator. The images were clean and crisp with no colour fringing observed. The limb did show a slight amount of secondary spectrum however, especially as the Moon drifted from the centre to the edge of the field. And just like that reported in my daylight tests on the tiled roof, I noticed that the image remained sharp all the way to the field stops.

Although a 90 degree diagonal is better suited to astronomical observations, I enjoyed some great views of showpiece double stars in the Spring Sky. Mizar and Alcor were beautifully sharp and moving up the sky to Polaris, I was able to cleanly resolve the faint magnitude 8.2 companion(Polaris B) easily at 60x. Later in the night as Cygnus gained altitude in the east, I enjoyed the gorgeous colour contrast double Albireo at 60x. With Delphinus about 20 degrees above the horizon in the wee small hours, I enjoyed splitting Gamma Delphini easily with the SA405 at 60x.

On nights where the Moon rose late or had set early, I went off in search of some of the more celebrated deep sky objects, such as the Double Cluster in Perseus, which was beautifully framed at 60x low down in my northern skies. The Beehive Cluster in Cancer presented excellently in this high-performance glass at 25x, with dozens of white and creamy white stars strewn haphazardly across the field. Turning to Leo now past the meridian and sinking into the western sky, I was still able to pick up the faint light from its most celebrated galaxies, M95, M96 and M105 just north of the star 53 Leonis. Turning to Hercules in the wee small hours of mid-April, the Svbony SA405 served up an excellent view of M13, the great globular cluster, now placed very high in the eastern sky.   

Solar Observing

The Svbony SA405 20x-60x ED also proved to be a formidable telescope for observing the solar photosphere. Fetching a homemade white light filter constructed from Baader Astrosolar material, I enjoyed some great views of the solar disk throughout late April and early May 2023, with lots of sunspot activity to be seen. Having become accustomed to viewing the Sun using my 20x 60 Pentax binocular, I was impressed how much more I could see with this larger aperture and higher magnification spotting scope. Now that we’re approaching solar maximum, this will be a great scope for monitoring sunspot activity in the months and years ahead.

My First Field Trip with the Svbony SA405 20x-60x ED

I took the SA405 spotting scope and lightweight photographic tripod to one of my local patches to suss out the local wildlife. I walked the half mile country road up to Culcreuch Castle Pond, carrying the scope in its neoprene case and the tripod. Once I got there, it took me less than five minutes to set the gear up and running to begin observations thanks to the built-in 1/4-20 tripod interface.

Unfortunately there wasn’t much activity at the pond on that particular morning, but my eye was drawn to a Grey Heron lurking in the reed bed on the east side of the pond about 150 yards in the distance. Curious, I dialled in the 20x to get an overview of the scene. I could see the Heron was concentrating intently, standing absolutely still as it glared at the water beneath it. I had seen this stance many times before using my binoculars, so I knew something exciting was about to happen. I quickly racked up the power to 60x and refocused using the helical focuser. To my amazement, the Heron thrust its long neck forward and grabbed a large frog from the reedbed. The frog’s head was clenched between its maxilla and mandible, its legs outstretched and kicking the air frantically as it contemplated its final hours. Moment’s later, the Heron swallowed the frog whole. But then, as I continued to watch the Heron, it made itself ready for another pounce, staring intently once again at the water beneath it. And then wham! Another large frog was caught up in its beak, and down it went into its tummy. To say I was shocked to see this through the scope would be an understatement. I had always assumed that these graceful, large wading birds fed on small fish and eels. Never did it dawn on me that it gorged on frogs too!

That wasn’t the end of it either. Within a few more minutes, the gluttonous Grey Heron had caught a third adult frog; yes a third; swallowing it live in front of my eyes! What an unforgettable few minutes! I would never have been able to get this close to this magnificent bird with my 8x or 10x binoculars, as they are notoriously timid, flying off at the merest hint of danger. I immediately appreciated the great magnifying power and clear and sharp images served up my this nifty instrument from this distant vantage. Lets just say this maiden experience consolidated my admiration for these marvellous optical devices, even though it did put me off my lunch.

A spotting scope like this can be used in different capacities, depending on your inclinations. Some will choose to use it to carry out simple visual observations. Others will like to Digi scope, taking pictures of wildlife etc with their own phones or cameras. Others may want to take it still further by attaching a dedicated digital imaging camera to the scope to take still or continuously live feeds. For example, Svbony’s dedicated SC001 2 Megapixel imaging camera can be inserted into the scope simply by removing the eyepiece. The SC001 camera has Wi-Fi connectivity to allow you to conduct still or live video feeds on your phone using the company’s App.

In this blog, I simply present a few images to the reader so that you can glean some more information about its optical performance. The following images were captured using my hand-held iPhone without a mounting device. Furthermore, the images are entirely unprocessed.

Conclusions & Recommendations

The Svbony SA405 20x-60x ED is an enjoyable spotting scope to experience. It’s very easy and intuitive to use and is very versatile, being more than capable of delivering great astronomical and terrestrial views. It’s perfectly at home on a lightweight photographic tripod or altazimuth astronomical mount. It delivers impressive images that most enthusiasts will be pleased with. Those wishing to explore other eyepieces can simply remove the supplied zoom eye piece and insert their own. This can provide even wider fields of view and potentially higher quality images. I write this in full knowledge that the SA405 is not the company’s flagship spotting scope model. That accolade goes to the SA401 20x-60x double ED scope, which can potentially serve up even sharper images for a few hundred dollars more.

I would recommend the SA405 to birders, general nature watchers and amateur astronomers who like to dabble in a bit of daylight observing. I think it represents very good value for money given the considerably higher prices commanded by more established sports optics firms like Opticron, Leica, Zeiss and Swarovski. And while it won’t match the performance of a $2k+ optic, it will do many things well and keep an enthusiast busy for years. In this capacity, it’s simply imagination limited!

See Part II which explores eyepiece options and imaging capabilities

Dr Neil English is a lifelong observer of the night sky but has, in recent years, broadened his horizons by delving into the weird and wonderful world of birding and nature studies. His new book, Choosing & Using Binoculars: A Guide for Stargazers, Birders and Outdoor Enthusiasts hits the shelves in the fall of 2023.

De Fideli.

A Work Commenced October 29 2021

Product: Svbony SV410  9-27x 56mm HD

Place of Origin: Hong Kong

Magnification Range: 9-27 x zoom

Aperture: 56mm

Objective Focal Length: 189mm

ED Glass: Yes

Field of View: 36-78m@1000m,(2.1- 4.5 angular degrees)

Eye Relief: 18mm

Close Focus: 2m(advertised), 2.16m measured

Nitrogen Purged: Yes

Waterproof: Yes IPX5

Dimensions: 19.4 x 6.6 x 11.8cm

Weight: 580g(advertised), 561g measured

Accessories: Rubber objective and ocular caps, protective scope jacket, lens cleaning cloth, carrying strap, Instruction manual.

Warranty: 1 Year(limited) 

Retail Price: £179.99(UK)

Svbony is a relatively new Hong Kong-based optics firm that began supplying amateur astronomers and nature enthusiasts with a wide range of cost-effective but good quality instruments and accessories in 2014. A google search of Svbony products will reveal a large and international fan base of customers who have been pleased with their eyepieces, filters, night vision devices and more recently, the company’s extensive range of astronomical and terrestrial spotting scopes.

My introduction to Svbony came as a result of testing out a trio of high-performance binoculars from their SV 202 range. You can see those reviews here, here and here. What astonished me most about these binoculars was their excellent optical and mechanical performance at prices that were simply unbeatable in today’s market. These experiences collectively whetted my appetite to explore some more of their products, and in this review I will be sharing my thoughts on their newly launched mini-spotting scope that combines weatherproof ruggedness with good optical performance, in an ultra-portable package; enter the SV 410 9-27 x 56mm ED spotter, which first appeared on the market back in April of this year.

The scope was purchased from Amazon UK for a price of £179.99, and arrived a couple of days after ordering. Readers may also purchase the instrument directly from Svbony via this link, which will allow you to purchase the scope more cheaply if you can tolerate a longer shipping time(usually about 8 days)The instrument came well packed inside a long, white box with the blue and yellow Svbony logo, and with all of its accessories neatly packed inside. The little spotting scope was carefully placed inside a snugly fitting black foam bed, carefully cut to match the angled shape of the instrument. The accessories included a comprehensive multi-language instruction manual, a lens cleaning cloth, a nicely machined protective jacket and carry strap. The scope itself came with good quality and tightly-fitting rubber ocular and objective covers.

Ergonomics

Right from the get go, I was very impressed with the build quality of the SV 410 mini spotter. It feels very solid in the hand but only weighs about the same as a typical 8 x 32 binocular. The metal chassis (possibly a magnesium alloy or aluminium) is overlaid by a mild green rubber armouring. The helical focuser, located between the objective and the eyepiece moves nicely with a good deal of friction. There is no facility for fine focusing like on larger spotting scopes, which offer a larger range of magnifications, but in use I found that it was more than adequate to get precise focus since the highest power (27x) is not large enough to necessitate a fine focus knob.

The zoom eyepiece is clearly marked with magnifications from 9x to 27x which you can choose simply by rotating the eyepiece to dial in your preferred power boost.

The nicely machined aluminium eyecup is overlaid with soft, black rubber and twists upward to provide the necessary eye relief for non-eye glass wearers. It clicks into place- and you can hear it!– without any play, and holds its position very well. Another good design feature of the eyecup is its continuous motion from fully retracted to extended -that means you can dial in your preferred eye relief. I found, for example, that the eyecups pushed slightly down renders excellent results without glasses.

The instrument is quoted as having an eye relief of 18mm, but I found it was a little shorter than this. I did however test the scope with the eyecup fully retracted with my eye glasses and I was able to see the entire field with no problems but it was fairly tight!

The objective and ocular lens coatings are different from those applied to their SV 202 binoculars, having a mild, greenish tint in broad daylight;

Unlike larger spotting scopes, there is no lens hood on the Svbony SV 410 spotter, although the objective is quite deeply recessed. Having a hood would afford greater protection against stray light during use in bright daylight but if push come to shove, one can easily be made from a cardboard or plastic sheath. I guess Svbony decided against having a lens shade to keep the weight down to an absolute minimum.

The underside of the mini spotter has a brass screw socket to enable the user to quickly mate it to a monopod or tripod in field use.

Overall, I was very impressed with the build quality on this nifty little spotting scope from Svbony; so small it fits snugly in the palm of your hand.

Optical Evaluation

My first test looked for stray light and internal reflections when pointed at an extremely bright light source. So on went my IPhone torch set to its brightest setting. After focusing the beam from across a living room, I was able to establish that the unit displayed excellent suppression of internal reflections, but also very little in the way of diffused light and no diffraction spikes. Just like their SV 202 binoculars, this spotting scope was up there with them in terms of controlling bright light sources. I confirmed this after dark by looking at a bright sodium street lamp. All was well, as I expected, with a nice clean image of the lamp with no annoying internal reflections or diffraction spikes. Once again, good job Svbony!

Looking at the exit pupil as the scope was racked through its zoom magnification range showed a nice round light shaft throughout. The images below show the exit pupil at the 9x setting and the 27x setting for reference:

Taking into the consideration the extremely fast focal ratio of this Porro prism spotting scope ( f/3.4), requiring four objective lens(one of which is an ED element) elements in three groups, I knew going in that the total elimination of chromatic aberration would be a tall order. But I was very pleasantly surprised when, after mounting the scope to a lightweight tripod, I racked it through its full range of magnifications, 9x through 27x, focused on a telephone pole set against a uniformly bright overcast sky. I noted that I could obtain a very sharp focus right up to 27x with only a modest amount of chromatic aberration seen around the edges of wires and the pole itself. Furthermore, any secondary spectrum seen was very sensitive to eye placement. I quickly learned to move my eye around to minimise it while observing my targets. In addition, moving off axis shows some lateral chromatic aberration in this scope.

The image is bright and sharp, with excellent contrast. Autumn colours really showed up beautifully using this small spotting scope from the Far East. The eyepiece is not parfocal however, thus requiring a significant amount of refocusing moving from low to high power  The zoom is continuously variable however, from 9x through 27x

The image remained very sharp right out to the field stop, with only very minor field curvature and pincushion distortion; much less severe than the vast majority of binoculars I’ve tested over the last three years!  I took the liberty of capturing some images through the Svbony mini spotting scope using my IPhone and a digi-scoping adapter.  The reader will bear in mind that these images were captured during the most adverse conditions possible with leaden rainclouds, windy gusts and outbreaks of rain. All the images are entirely unprocessed and were taken directly from my IPhone.

First up, an image of some fence posts at just under 44 yards distant. The reader will note the magnification was set to 27x and shows extremely mild field curvature at the edges of the field.

A wooden fence located at a distance of 43.8 yards, captured during very inclement lighting conditions. Next up, an image of a wooden outhouse roof about 20 yards away, showing the brilliant autumn colours coming though in the spotting scope set at 27x:

The image blow shows autumn leaves at 24 yards distance, power of 27x:

In my most severe test conducted, I took a shot of a telephone pole at a distance of 35 yards at 27x, showing some secondary spectrum. The reader will note that the amount seen by the naked eye is much less than the IPhone 7 captures:

Finally, I took a picture of a BlueTit at the birdfeeder in my back garden: 15 yards distance, 27x:

Further Notes from the Field

I measured the close focus on the Svbony SV 410 mini spotting scope to be 2.16m or 7 feet, just a little longer than the advertised 2m. That’s an excellent result, closer, in fact, than a raft of other spotting scopes I’ve looked at. The nearest I got was 2.5m for the Opticron MM4 50 ED, and even the closest product to the Svbony – the Celestron Hummingbird 9-27 x 56 ED – has a close focus of nearly 10 feet! That’s great news for those who would like to use their spotting scopes as long range microscope. It’s quite amazing to be able to look at flowers, fungi, rocks, insects, and a host of other things at very close range at powers up to 27x. That, in my opinion, greatly increases its versatility.

Because it’s so small, the little Svbony spotter can be carried in a wide jacket pocket or a rucksack. Stable handholding is eminently possible at a power of 9x, but at higher powers it does benefit from some sort of makeshift support such as a beanbag. I was able to stabilise the image completely by resting the spotter on the branch of a tree while viewing a pair of Mute Swans at one of my local patches, when I could exploit the entire magnification range of the instrument.

For more hassle free results, it pays to mount the spotter on a monopod, and because these are very lightweight and fold up to very convenient sizes, they can be carried about in a rucksack, with no hassle to the rambler.

This would be a good place to compare and contrast some of the specifications of this Svbony mini ED spotting scope to an outwardly similar instrument – the Celestron Hummingbird 9-27 x 56mm ED. As well as having a significantly closer focus than the Hummingbird, it also sports a wider field of view. The Svbony has a field of view range from 2.1 to 4.5 angular degrees, as compared with the Hummingbird at 1.9 to 4.2  degrees. This makes object acquisition that little bit easier with the Svbony The eye relief is also better on the Svbony mini spotter (18mm as opposed to 15mm). Furthermore, the Svbony is about 30g lighter than the Celestron scope. But perhaps the best news of all is that the Celestron Hummingbird ED mini spotter retails for about £299.99. That’s a 66 per cent mark up in price compared with the Svbony! Is the Hummingbird really any better? I have my doubts!

Notes Gleaned from Looking at the Night Sky

Reviewers who only carry out terrestrial observations during daylight hours are prone to miss some important details about their subject instruments. As a case in point, I use my right eye for astronomical viewing through all my telescopes, and this little Svbony was no exception. At 9x I noticed the mild astigmatism in my own eye was showing up in images of bright stars in the spotting scope’s field of view. But when I cranked up the power to 27x, the astigmatism was noticeably less. Viewing with my glasses on effectively eliminated this astigmatism. Had I confined my viewing to daytime targets, I would be none the wiser to this aberration originating from my own eyes.

Star images remained nice and tight nearly all the way to the field stop at all magnifications, just as the photos above reveal. The instrument clearly has a very flat and well corrected field.

The Svbony SV 410 mini ED spotting scope proved to be an excellent instrument for observing the Moon, which I enjoyed doing over a couple of weeks in October. There are no annoying reflections and diffraction spikes in the images it served up. A great amount of detail was gleaned at 27x; craters, maria, valleys and mountains all showed up with beautiful sharpness and contrast. I detected some slight fringing at the lunar limb, but this was also sensitive to eye placement. In comparison to my 20 x 60 Pentax PCF binocular, the Svbony showed slightly less colour fringing on the Moon but was its equal for sharpness and contrast – a very good result indeed, as I rate the latter very highly as a Moon-gazing binocular.

Bright stars like Vega reveal a trace of secondary spectrum at the highest powers as does the bright planet Jupiter, but I was just able to make out two bands straddling the planet’s equator and the four large Galilean satellites were very clearly discerned as tiny stellar-like point sources. I was also delighted to see Saturn’s majestic rings with the little Svbony spotter, and even its largest satellite, Titan.

In the late evening of October 30, I enjoyed a long clear spell with the waning Moon out of the sky. Mounting the spotter on my tripod, I examined a suite of double stars to test the resolving capabilities of this pint-sized scope. My first target was Mizar & Alcor low in the northern sky, where I was able to prize apart the tight companion to Mizar at 27x. Albireo( Beta Cygni) was beautiful and easy at powers above 12x, but most compelling at 27x. The view of the celebrated binocular multiple star system Omicron^1 Cygni was gorgeously presented at 27x, the wonderful colour contrast of its components coming through clearly. The components of Beta Lyrae were also cleanly resolved, and an especially lovely sight at 27x. Perhaps my most challenging split came when I turned the instrument on the orange star Gamma Delphini, now sinking into the west south-westerly sky. Taking that little bit extra care focusing this system at 27x revealed the prize I had been looking for; its fifth magnitude companion being just resolved with a steady gaze. This will make an excellent instrument for observing traditional binocular doubles, allowing you to study them at significantly higher powers than regular binoculars!

The main body of the Pleaides was nicely framed in the 2.1 degree true field of the Svbony SV 410 ED spotting scope at 27x. Many dozens of stars filled the field from edge to edge, including many double and multiple star systems easily discerned at the highest powers available to me. What appeared very odd to me at first, was the orientation of the stars making up this most celebrated herald of autumn. Of course, it presents the view as the eye sees it(only magnified), but being very accustomed to viewing stars through Newtonians and (in a former life), small refractors yielding upright but mirror-reversed images, it took a bit of getting used to in this quirky little spotting scope. Pointing the scope much higher up in the night sky showed me a very nice view of the great Galaxy in Andromeda(M31), together with its fainter companions M32 near the core, and M110 about a degree off to the northwest of the core of M31. The Double Cluster in Perseus, now near the zenith, stood out beautifully at 23x against a jet black hinterland. The Coathanger asterism in Vulpecula was an awesome sight at powers between 15x and 23x. And while sinking quite low into the north-western sky, I enjoyed some very fine views of M13 and M92 in Hercules.

As local midnight approached, I began observing the trio of Messier open clusters in Auriga. At 27x, one can begin to resolve these celebrated clusters into dozens of individual stars.  Later on again, in the wee small hours of Sunday morning, October 31, I went in search of M35, that wonderful, sprawling open cluster in the northern foot of Gemini, and was rewarded by a very compelling sight at powers above 20x, when several dozen of its brightest luminaries began to be resolved in the spotting scope. That weekend night vigil convinced me that a great deal of astronomy can be done with such a tiny scope as this. It’s very easy to find objects at 9x before zooming in for a closer look.

Conclusions & Recommendations

My experiences with the Svbony SV 410 9-27 x 56 ED spotting scope have been very pleasing indeed. Its low cost, solid optical performance, ease of handling, outdoor ruggedness and very light weight will appeal to a great many individuals wanting to make a move into the high magnification world of sport optics. And while not a full-sized instrument with its larger aperture and magnification range, this pint-sized scope will fill a niche for many, serving multiple purposes as a rich field travel and spotting telescope, as well as a high-powered long range microscope that you can take with you anywhere.

Highly recommended!

Neil English is the author of seven books in amateur and professional astronomy, including one on refracting telescopes.

De Fideli.