Re:ATM Cassegrain as second telescope project.

[William Mc Hale <wmchal1@umbc.edu>]

On Tue, 6 Aug 2002, Richard Foulk wrote:

>
> } I've thought about trying a cass system, since my first abortive
> } attempt decades ago. Back then, I tried making the secondary out of a
> } lens that had the approximate RC required.
> }
> } My biggest stumbling block was the thought of having to make one or
> } more extra mirrors just to test the system.
> } One secondary testing "method" I though about using was not to test
> } the secondary at all before use. Give the primary as good a
> } paraboloid as you can achieve, then star test the secondary, until
> } the system performance is good.
> }
> } Another option would be to use the Dall method to test the secondary.
> } It doesn't require making any extra test surfaces.
> }
> } Frank
> } --
> } Frank Henriquez  Programmer/Analyst  Jules Stein Eye Institute, UCLA
> } frank@ucla.edu   http://www.bol.ucla.edu/~frank/index.htm
>
> I've been toying with the idea of grinding the concave inverse of
> the secondary, to make it easier to test, and using that as a mold
> for a carbon fiber mirror.
>
> Just a crazy idea ...
>

If you are going to go through all of that trouble, why not just make a
Gregorian instead?

Bill

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