Re: [ATM] 8" Diagonal- More info

[Mark Holm <mdholm@telerama.com>]

Polaraligned wrote:

> Holding 1/10 wave or better is the priority and I know that the 
> edges are going to fade from this value.

Pardon me for being blunt, but why the emphasis on surface accuracy for
an instrument to be used at prime focus with a ccd camera?  Your
resolution is going to be nowhere near diffraction limited, instead, it
will be pixel size limited.  I'll bet, a calculation would show you can
tolerate wavefront errors that would horrify a planetary or double star
observer and still produce ccd images not even measureably below
"perfect" quality.

Maybe save some money by putting looser specs on that huge diagonal and
put the money into a quick change arrangement on the secondary mount, so
you can switch to a smaller, higher quality diagonal for visual use.

Mark Holm
mdholm@teerama.com

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