Re: ATM Advice on Large Spherical Mirror?

["Bob May" <bobmay@nethere.com>]

Was there another one there?  I'd love to have something like that as it's a
great Hindle Sphere for one.  The central hole is a bit large but that can
be worked around.
If you want to use it in a scope, you can always make a corrector plate for
it and do it as a Ritchey-Chrechain with the correction of the primary on
the corrector plate rather than on the surface of the primary.  It would be
interesting to look at what happens when the hyperbolic surface is generated
by the corrector as opposed to the primary surface.  I may be that a
corrector will make the abberations of the final image a bit less.
Bob May
http://nav.to/bobmay
bobmay@nethere.com
NEW! http://bobmay.astronomy.net