[ATM] Aplanatic Gregorian (was: 25" mirror possibilities)

["lou krajci" <loukrajci@comcast.net>]

>From: Michael Peck <mpeck1@ix.netcom.com>

>...Unfortunately the standard ATM
>reference on telescope design (R&vanV) doesn't discuss Gregorians in any
>detail, so most ATMs don't realize they are basically the same class of
>telescope.

Bingo.  My point exactly.

>Modern texts like Schroeder's "Astronomical Optics" or Wilson's "Reflecting
>Telescope Optics" treat all two mirror designs as a single family. Neither
>of those are aimed at ATMs, but in my opinion every serious ATM should own
>at least one of them.

At around $100 each?  (And isn't Wilson's book in two volumes?)  Ouch.
That's a big price for many ATM's.


>From: Mauritz Andersson <mauritz@physi.uni-heidelberg.de>

>For those of you with access to Applied Optics journal,
>the following is a great reference on two mirror aplanatic designs.

>Rimmer, Wetherell
>"General Analysis of Aplanatic Cassegrain, Gregorian and Schwarzschild
>Telescopes," Applied Optics, Vol. 11, 1972, p. 2817.

Another big price for the average ATM.

While the suggestions above are well-intentioned, they won't help any but a
few hard core ATM's.  Where does that leave the rest of us?

I will keep studying Mike's spreadsheet...and then ask him some questions
about symbology and how to use it to whip up aplanatic Gregorians.  If
nothing else...maybe we can come up with some simplifications/rules of
thumb...some starting points and examples for ATM's to start from.

Tom Krajci
Albuquerque, New Mexico
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