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


At 14:27 2003-07-21 -0400, James Lerch wrote:

>Ok, Let the FUN begin 
>
>Unit = Waves
>Wavelength = 633nm
>
>RMS Wavefront = 0.145  {46nm Surface}
>PV wavefront  = 0.67       {212nm Surface}
>Strehl Ratio    =  0.44

A small part of the fun, illustrating "waves" in mirror
evaluation:  46 nm surface RMS gives only 0.331 Strehl ratio using the
standard evaluation wavelength of 550 nm, but the quoted .44 Strehl using
the test wavelength 633 nm.  Oh well, the mirror's not close to passing,
.44 would be a D mirror, .33 D-minus .

>Astigmatism   =   0.40  83.3deg
>Spherical = -1.43
>
>So, we have astigmatism.  I imagine 0.4 is not a "good thing"

If the 0.4 astig (whatever the units) is included in the 46 nm surface RMS,
then you've got the whole answer.

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

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