Re: [ATM] Astigmatism in round robin mirror C with Foucault.

["Don Ware" <mimas@charter.net>]

Some time ago a friend brought over a mirror for foucault and
interferometer testing.  Interferometer results showed
considerable astigmatism and the results didn't changed as the
mirror was rotated so I'm certain it was in the glass.

I then tested it across several diagonals WITHOUT rotating the
mirror using my multi-plane robo-foucault tester.  The results
were clearly different as the tester was rotated.  I've measured
the tester-mirror movement during rotation using a run-out gauge
and it's much less than .001"  My feeling is that I should be
able to get some useful information from the multi-diagonal
testing, but as the interferometer measurements are so much
easier, I've never attempted anything.

Don Ware
http://webpages.charter.net/dware1/


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