[ATM] PLOP and UltraThin Interferometry compared

[Dale Eason <atmpob@yahoo.com>]

I thought it might be fun to compare PLOP and my
interferometery of the 16 x 3/8 plate glass mirror.

My image was made with the mirror on the test stand
tilted back 45 deg (close as I can get to horizontal.)
Lateral support pegs at 90deg.  I have tried them at
30 deg and there is not much difference except I can
create a lot more astigmatism when they are at 30 deg.

What I did learn is that the high area from pads to
edge caused by completely by the pads and not by the
forces from the lateral support.

I have subtracted the known mirror error from this
image to get mostely test stand error.

http://home.comcast.net/~doeason/DDavis/3pegs_contour_mirror_removed.jpg

PLOP image
http://home.comcast.net/~doeason/DDavis/plot_3pegs_125.jpg

You can see that they are similar.  Some of the
difference is due to the astig caused by the lateral
support and the mirror not being horizontal. 

I have not compared actual height values because the
mirror is not horizontal.  Can anyone tell me how to
modify the mirror material to simulate .7 gravity?  I
assume you would modify the material terms by .7 but I
don't know which ones. Modulus, Poissons, Density, or
all.

Dale Eason

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