Re: ATM AO and Youngs Modulus for glass

["Benoit Schillings" <benoit@be.com>]

>>
>This is intended to go on the back of the 20" Cass, but have gotten 
into the
>AO
>system and the 20" blank is still in the box...  The wave front sensor 
is
>together and seems to function well.  It is a Shack Hartman type with 
4 sub-
>apertures.  This 
>is enough to sense the first 5 Zernike terms (tip, tilt, focus, 
astigmatism(0)
>and Astigmatism(45)).  All 4 are focused onto a single CCD (Cookbook 
245).

Greg,

I don't think that you want to use a CB245 as a wavefront sensor... the 
readout
noise (30 to 40 e-) will be a big limitating.

How about a GEN II intensified camera... this will give you 60 Hz 
readout
speed and a much better sensitivity.


                -- Benoit