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Re: [ATM] Cassegrain vs. Gregorian



Bob May wrote:
> Personally, I'd rather build a concave secondary with an e of about half a
> parabola than build a convex secondary with a hyperbolic e of about 4 times
> that of a parabola.
> Concave surfaces I can test with a Foucault tester while a convex surface
> needs a large spherical mirror to test.

(semi-rhetorical)

So, what you're saying is that you don't mind removing 3 to 5 times as
much material during the figuring process, since you know you can do
it more accurately?

> Bob May

-- 

Rick S.

http://users.rcn.com/rflrs

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