Re: [ATM] Please help me figure?

[Jim Burrows <burrjaw@earthlink.net>]

At 2004-06-09 22:20 -0500, Rich Ball wrote:

>Would someone with experience describe the strokes I need to bring an 8" 
>f8 mirror back to sphere after having  been figured too deeply?

I'd suggest doing a Foucault test to see where you really are.  If you 
already have and the test says over-corrected (which might be the meaning 
of "too deeply"), then a 1/3 COC stroke will move the mirror back toward a 
sphere (MOT or TOT - no difference).  The thing is you will pass a parabola 
on the way, maybe close enough to be done if you're lucky (8"f/8 isn't very 
demanding), so keep testing often.

         -- Jim Burrows
         -- mailto://burrjaw@earthlink.net
         -- http://home.earthlink.net/~burrjaw
         -- Seattle N47.4723 W122.3662 (WGS84) 

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