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    Observing the Moon with a spotting scope

    Couple of days ago I took my Kowa TSN 883 spotting scope to see the Moon as it was very high on the night sky. Seeing was very good so I installed APM 3.5mm XWA 1.25" astro eyepiece to have about 145x magnification and the view was very crisp, lots of detail to be seen. APM 3.5 XWA has very...
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    EL 12x50 swarovision eyecups (inadequate eye relief)

    Are any other (NL, SLC, EL range) model eyecups compatible with EL 12x50 Swarovision (pre Field Pro version to be spesific)? My problem is inadequate eye relief as the eyelenses are deeply recessed/the eyecup rim is too high so usable eye relief is lost by several mm. Maybe one solution could...
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    Is there a bird?

    I should not make this too easy this time so: I'm asking if there is a bird (I'm not saying that there is though) and if there is a bird, how many (I'm still not saying there is a bird at all and even if there is I'm not saying that there couldn't be more than one) and what species? Regards, Juhani
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    EF 300/f2.8 L IS USM II + 2x II + 2x III extenders

    Experimenting stacking two 2x extenders (II and III version) and trying to photograph the moon using 7D MkII. ISO1000, 1/125, f11. Camera doesn't recognize the other extender and autofocus doesn't work. Regards, Juhani
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    Spotting scope for casual astronomy, or something else?

    I currently have Kowa Prominar Tsn-883 spotting scope which I use for moon and planets. Often with 1.6x extender with 25-60x TE-11WZ zoom but sometimes also APM 3.5 mm 1.25" eyepiece. In good seeing these can give very pleasing image quality and details (in my opinion), even the 3.5mm @about...
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    Find the bird?

    Picture taken 13/6/2020 in Finland. Regards, Juhani
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    Canon EF 400/f5.6 L USM + EOS 7D Mk II combo anyone???

    I used this set (bought secondhand of course) about 7 years before I had EF 300/f2.8 L IS USM II (which was waaay too expensive, even secondhand, for an amateur photographer like me). Allthough 300/f2.8 L IS is more cabable and versatile (excellent with the 1.4x teleconverter and very usable...
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    Best tripod head for spotting scope?

    I currently have Sirui VH-10X head which is quite good. Anyway it has developed some problems as the click stop mechanism is jammin every time I put my scope (Kowa 883) on it and also the locking mechanims isn't 100% tight as the plate slides away from the balance point if I carry the tripod on...
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    Is there a bird?

    Photo taken 11/5/2020 in Finland. Regards, Juhani
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    Observing Jupiter with a spotting scope

    Yesterday evening I tried to observe Jupiter here in central part of Finland. Weather was clear but some air currents were deteriorating the seeing. Nevertheless I had maybe the best views of Jupiter so far using my Kowa Tsn-883 spotting scope with the 1.6x extender. Two dark bands were showing...
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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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