RE: [APML] TV-85 or ?

[Alan Voetsch <avoetsch@mail.com>]

Thanks David,

This is a fairly complete analysis. I would like to hear about any
photograhic comments you or others have regarding this or other scopes in
this size range.

Clear darkness
Alan


>>>102ED = 8.82 lbr
125 mm rings = 2.2 lbr
dovetail = 2.5 lbr
total = 13.52 lbr<<<



>>>1) Difraction: absolutely perfect difraction rings at 300X
2) Chromatic aberration: it is hard to beleive using only two glasses, but
mine is absolutely free. I am really impressed about that
3) Spherical aberration: undetectable
4) Astigmatism: moderate astigmatism near the edge of the field using a 26mm
eyepiece, undetectable with a 14mm eyepiece
5) Mechanical: not as good as a TV but enough stiff for astrophotography
6) Focusing: a little bit tough when cold
7) Back aperture: 60 mm

I was told TV-85 is better in all aspects than the 102ED, but I beleive the
102ED is the best APO for its price range, at least in Spain. Now I am
waiting for the 60 mm wide photo adapter for my 102ED (the simplest way to
avoid vigneting) so I have not taken any "serious" photograph yet. If you
want as soon as I have any result I will send you the corresponding
report.<<<


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