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    Berlebach UNI tripods?

    I currently have Gitzo 3542L carbon fibre tripod, which is lightweight but still reasonably steady for my Kowa 883. If the winds get high, there will be vibrations, which can to some extent be reduced by attaching weight to the center column. I have been thinking to get a heavy wooden tripod...
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    10x alphas with good eye relief

    Hello, I currently have Swarovski SLC 10x56 HD which has enough eye relief for my glasses and has also optically really nothing to whine about. Why I might consider getting a new binocular would be because I would need more near focus (about 2m would be very good), could carry something less...
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    Resolution calculations

    Hi, I (finally) ordered Edmund Optics USAF 1951 pocket size resolution target and would like to know the formula how to convert the results to arcseconds? Regards, Juhani
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    ATX95 chromatic aberration etc.

    Hi, I was wondering how well corrected longitudinal CA is with ATX95; how much color fringes are visible at the image center at 70x (or higher mag. with the extender)? How does ATX's performance compare to (in this area often praised) Kowa Prominar 883? The thing is; with my Kowa 883 I can...
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    Star testing Atx95 sample

    Had an opportunity to quickly test my friend's Atx 95mm scope. Light source was improvised with silver fishing reel at sunlight, distance about 20m, not too much heat haze. Inside and outside patterns were practically identical; just some ovalness caused by astigmatism but not severe. No prism...
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    Two Kowa Prominar 883 samples

    Hi, today I had a chance to briefly star test two Prominar 883 samples. I also did a basic comparison using 20€ bill as a target with my own Prominar 883 sample and Zeiss Victory Diascope 85 FL as a reference scopes. I tested these all with their zoom eyepieces @60x. I have earlier posted star...
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    Depth of field

    Hi, I'm wondering what factors affect to the depth of field on spotting scopes (or binoculars also). It's clear that magnification is one of them but is it the only one? Does aperture or focal ratio have any effect? Are there some optical aberrations or defects (miscollimation?) that can...
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    Moon through Kowa Prominar 883 + APM 12.5mm + 1.6x extender

    This picture was taken with Samsung A50 phone camera using Opticron universal phone adapter. The camera is not perfectly centered so there is some fringing on the edge of the right side especially. Juhani
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    Zeiss Victory Diascope 85 t* fl star test pictures

    Hi, here are star test diffraction patterns for Diascope 85 fl inside and outside focus. Zoomed to 75x and light source was silver flagpole knob about 40 meters away. I think there is not anything else wrong with it but some spherical aberration is involved. In direct comparison with my Kowa...
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    Televue Delos vs. Baader Morpheus astro eyepieces on spotting scope

    Hi, I have at the moment Baader Morpheus 12,5 mm eyepiece which I use with my Kowa Prominar 883. It gives about 41x magnification and 76 degree fov. I use it mainly on birds in flight, especially predator and migratory observing. It feels pretty good optically, eye placement isn't perfectly...
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    Kowa Prominar 883 star test pictures

    Hi, here are inside and outside focus star pictures shot through my Kowa 883 + 25-60x zoom + 1.6x extender (zoomed 60x * 1.6x =96x). The artificial star I used was made by instructions given by Joachim in various posts here on Birdforum. Thin aluminium foil perforated with needle and placed on...
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    Baader Hyperion Mark IV zoom on Kowa 883 Prominar

    Hi, I got Baader Morpheus 12.5mm eyepiece for my Kowa 883 and found it to be very nice to look through. It seems to be brighter than Kowa's TE-11WZ zoom (at about 40x mag.) eyepiece and maybe even little sharper. It also has very wide fov (76 degrees). I haven't done any resolution comparison...
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    Effects of optical aberrations

    I have lately been doing star tests with couple of scopes and have been wondering this: If we assume one would have four otherwise identical scopes but of which one would be aberration free sample and three other would have miscollimation, astigmatism and spherical aberration (each of the three...
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    Story of two Kowa Prominar 883 scopes

    Hi to all, after I made a deal with the seller that I can test the sample and have the right to return if it's proven optically bad one, I ordered Kowa Prominar 883 + 25-60x zoom eyepiece. I star tested the first sample right away when it was arrived and quickly concluded that it had...
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    Meopta S2 82 HD performance

    I'm considering to buy Meopta S2 82 HD probably with 30-60x WA eyepiece. I would be interested to know if the focus ring becomes smoother over time, because many have stated that it is rather stiff (at least when new)? It's also quite fast and it may be an issue for me because I can remember how...
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    Light transmission of spotting scopes

    Hi to all, is there data of light transmission measurements for top quality spotting scopes anywhere available? Often manufacturers announce light transmissions for binoculars (at least if it is >90%...) but rarely for spotting scopes. This may be stupid question but I was just wondering...
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    Leica Apo televid 82 vs. Meopta S2 82 HD

    Hi to all, I’m planning to get new spotting scope to replace my Leica Apo Televid 82 + 25-50x. I’ve had my Leica about 7 years now and been quite happy with it. The main reasons I want to get new scope are: Leica’s magnification is somewhat limited by the maximum of 50x (there are no other...