From: "Matt Considine" 
To: "Richard F.L.R. Snashall" 
CC: atm{at}shore.net
Reply-To: "Matt Considine" 


The back can be curved - it doesn't need to be flat.  In fact, if half the
required curvature is
put on both sides of the plate, you avoid having the back of the plate act
as a flat reflector
for ghost images.

If I understand that design correctly, shouldn't the figure of the
"secondary" spot have the
same polynomial coefficients as the corrector surface it sits upon?

Or are you putting two different curves onto the plate?  Wouldn't that be
tough to make?

Matt
(who hasn't made a plate yet)

> 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

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