Re: [ATM] Offner layout question - links-corrected

["vladimir sacek" <vla@toast.net>]

>... For a 30" F/4 it would come to more than 7 waves PV
> wavefront error of astigmatism (use the infinity-object mirror F# in the
> formula).

I just realized that I didn't halve the offset angle. That makes the 
astigmatism four times smaller, or ~1.8 wave PV. More than enough to spoil 
the null, *assuming* the mirror is near perfectly supported/suspended. If 
not, it would actaully tend to offset astigmatism resulting from the sag. A 
bit dicey, but can work well, if you're lucky.

Vlad


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