Re: [ATM] 7 inch spherical mirror

[Alexis Cousein <al@sgi.com>]

Dominic-Luc Webb wrote:
> I need to look back at some of my earlier simulations to see
> how coma looks with the two surface profiles (parabola
> vs sphere) when they are both stopped down. 

IIRC, for an aperture some distance in front of the mirror, you
can reduce and even eliminate coma for a sphere, whereas for
a paraboloid the stop distance has no effect on the coma.

IIRC, the coma is canceled for a stop at a distance of
1/(1+K) times the radius of curvature (with K being
the conic, K>-1).

-- 
Alexis Cousein                                  al@sgi.com
Senior Systems Engineer/Solutions Architect     SGI/Silicon Graphics
--
<If I have seen further, it is by standing on reference manuals>

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