ATM Re: Corrector plates

["Frank Q" <frank@katestone.com.au>]

Hi Richard/All,

This is an interesting idea.

The plate would take the shape of a meniscus lens (sort of) or
perhaps a mak corrector (again - sort of) with the 4th order
schmidt polynomial figured on a surface.

If we make it bulge towards the mirror, we can make the surface
spherical (D-K); hyperbolic (CASS) or if we turn it around (bulge
away from mirror) we could make it elliptical like a gregorian...

The possibilities are interesting and numerous !!

By the way, has a gregorian with a spherical concave secondary
(all corretion relegated to the primary) ever been designed/built????

Cheers
Frank Q

----- Original Message -----
From: "Richard F.L.R. Snashall" <rflrs@rcn.com>
To: <atm@shore.net>
Sent: Thursday, January 23, 2003 12:12 PM
Subject: Re: ATM An Old TMs Simple Query


>
> As long as we are asking questions about Schmidts...
>
> I have wondered for some time "Why the Schmidt always had a flat
> corrector plate?".  If it could be curved, the backside could
> then be used as a Cassegrain secondary, similar to that used in
> the Gregory Maksutov.
>
> I have added something like what I am asking at:
>
> http://users.rcn.com/rflrs/newsch1-04x.len
>
> I'm not saying it's good, but I think it at least gives an idea
> what I'm talking about.
>
> Rick S.
>
>  >
>  > Talk with you soon,
>  > Coyoté
>
>
>