[ATM] RE: 25" mirror possibilities

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

>From: "Richard F.L.R. Snashall" <rflrs@rcn.com>

> > Question for the group:  are there variants of the Gregorian (let's call
> > them 'compensated Gregorians') that use a non-paraboloidal main
mirror, but
> > a concave secondary that can still correct for spherical aberration...so
> > that you have perfect on-axis images.  (Or does this end up with a
design
> > with the focal plane in a strange place...like in front of the main
mirror?)
> >

>Yes.  Any of the forms described in:

>	http://users.rcn.com/rflrs/twomirrors.htm

>can apply to a Gregorian form as well as the Cassegrain.  (The
>one with perfect on-axis images is the Classical.)

Thanks!

I'll have to investigate this for possible future projects.  I don't need an
overly large field that's well corrected, and this may meet my needs.

Tom Krajci
Albuquerque, New Mexico
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