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


At 17:55 2003-08-04 +0930, John Murray wrote:

>At Mark Holms' suggestion, I set the KE so zone 0 was balanced. I then
>measured
>from the centre of the blank to the light source/knife edge. This gave a ROC
>of 2005 mm.  So now the revised information with 4 sets of readings are as
>below.

And the revised Sixtests input file is
-------------------------------
John Murray
      197       46
Foucault
        0
y, mm    X, mm
39.3            0
62.7         0.22
79.0         1.35
92.4         1.63
*
       -1        0
     0.26
     2005
-----------------------------
Not much change in the surface RMS, 18.7 nm = .833 Strehl, and there's now
agreement with Mark that the mirror is a tiny bit overcorrected, b =
-1.055.  The .26 mm reading standard deviation gives a 6.6 nm sigma in the
RMS estimate.  A quick look at a normal distribution table says there's a
.42 probability that the mirror doesn't pass (RMS > 20.0 nm).  The main
problem the surface plot shows is the peaks and valleys between the center
and edge, suggesting the figuring prescription of Texereau's
"normal" stroke, 1/3 CoC + 1/4 W, in an attempt to smooth them
out.  Once again, only 1-2 minute spells between tests to see what reduces
the RMS.

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

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