From: "Jack Schmidling" 
To: 
Reply-To: "Jack Schmidling" 


From: "Frank Q" 

> A Lurie-Houghton is a design using a 2-component (2 lens) corrector.
> The design features are:
>
> * ALL surfaces are spherical
> * Flat focal plane (well, almost flat)
> * Corrector has zero power so chromatic aberration is small
(insignificant)
> * Corrector has bi-convex and bi-concave components.

Sounds scary.  I assume this corrector is at the eypiece not in front like a Schmidt?

> I don't know what your situation is with a parabolic primary (I assume)
> or whether you could modify the corrector to compensate for the
> parabolic primary.....

I would rather make a new mirror.

BTW, I bought a cute little scope from Orion for my son a few years ago
that consisted of an F3 sphere and some sort of corrector in the focuser
and it was a piece of junk.  Hard enough for me to collimate and impossible
for him and when perfect, only the very center of the field would be in
focus.  Is there any connection here?

> Would you like me to email you the program so you can try a few
> configurations ??

Sure, be fun to ponder.

js

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