> Catadioptric scopes (those with a corrector lens at the front) are made
> in two optical designs... either Maksutov or Schmidt-Cassegrain. The
> Maksutov corrector plate is a very thick meniscus lens with the
> secondary mirror being an aluminzed spot on the back of the corrector
> plate. The Maksutov design is used for mirror camera lenses, spotting
> scopes and astronomical telescopes. The corrector plate gets heavy and
> hard to manufacture as the aperture goes up. The Questar 7-inch
> telescope may be the largest commercially available Maksutov design.
>
> The Schmidt corrector plate appears to be a flat piece of glass with the
> secondary mirror mechanically mounted via holes drilled in the middle.
Vixen makes a telescope VISAC (Vixen's 6th Order Aspherical Catadiptric)
which has a Ritchey-Cretion (spelling??) design. This scope boasts
pinpoint sharp stars (0.35 micron or 35 micron??) till the edge of 35mm
film. I bought this scope 3 years ago.
This scope also lead me to the purchase of my first Olympus OM-1 last
year which now my Oly system has grown to an OM-4Ti plus a few lenses.
Although I've yet to come up with an astrophotograph with my gear, you
lot will be the first to know and see when I do :-).
Sean
--
Sean H.Y. Chan ICQ# 28162308 sean@xxxxxxxxxx
IT Consultant http://www.tsm.com.au/~sean
DSM Group Pty. Ltd. +61 (0)500-888-117 (W)
PO Box 1493, West Perth, 6872, WESTERN AUSTRALIA
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