To: atm{at}shore.net
From: Jim Burrows 
Reply-To: Jim Burrows 


At 23:08 2003-03-21 +0000, Marco Miglionico wrote:

>Could one, in practise, measure the wavefront effects of various support
>cells on the mirror using Foucault (or other) apparatus?

You could use the Foucault test, but it would be tough.  You need an
L-shaped knife edge and a mask with holes along a horizontal and vertical
diameter.  Run the Foucault test and data reduction for each diameter,
average the two best-fit RoC values, then run the reductions again with the
RoC fixed at the average value.  This no-motion test is required to
evaluate primary astigmatism which is probably the major aberration from
supports & thin mirrors.

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

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