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Kowa TSN 821 with Baader zoom eyepiece (1 Viewer)


New member
United Kingdom
Can anyone confirm that the Baader hyperion mk4 zoom eye piece 8mm-24mm will fit a Kowa TSN821 body without any adaptors, fiddles etc.
And what magnification range will that give ie 20x- 50x etc.
I have the Kowa 821 and the 32x eyepiece, and people have said that the Kowa 20-60x eyepiece is not very good, but I would like the option of a bit more reach.


Well-known member
I can confirm that the Baader Hyperion Mk IV zoom fits the external threads of the Kowa 820 series via the eyepiece main collar.The range extends ,yes,to almost 60x,but the 821 has a fairly short focal length and uses standard glass,so the image shows chromatic aberration.This is present at all magnifications ,but from 30x to 60x the degradation of the image would be more and more noticeable ,to the point of making the extra magnification not worth the trouble .A good unit would still get some decent detail in certain conditions,but in challenging light and long distance its going to be difficult to see most of the time.I say this because the Baader Mk IV its an investment of 200 or 250 pounds ,and perhaps an upgrade to an ED scope would make more sense if long range observation is the ultimate purpose of your eyepiece upgrade decision..

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