Re: [ATM] Hello & Mak Newt specs

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

Max Mirot wrote:

> What happens to the aberrations when the distance between the corrector 
> and
> mirror are changed?

Nothing much for relatively small changes; spherical is practically 
unaffected;
coma changes approximately with 3(s-s')/2(1-s), and astigmatism with
[(1-s')/(1-s)]^2, s~0.4 being the typical mirror-corrector separation
in units of the mirror r.o.c and s' the new separation.

So if you reduce the typical separation by, say, 5%, there would be
no appreciable effect on the size of spherical aberration,
coma would increase by ~5% and astigmatism by ~7%.
A 5% separation increase would result in a similar coma/astigmatism
reduction.

Vlad 

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