From: "Sidor . Kurt" 
To: 
Cc: 
Reply-To: "Sidor . Kurt" 


My previously described crude "FEA" wavefront analysis method
would work for this inquiry.

My decription can be found in the Archives here:
 http://astro.umsystem.edu/atm/ARCHIVES/OCT02/msg00284.html

 It would have to be modified with a scale factor to proportionally change
the amplitude of each contributing element across the aperture
proportionally to its unique, local transmisivity/reflectivity.  This would
enable the testing of chips, obstructions, spiders, appodization masks,
ect. The hardest part is mathematically defining the apertures parameters
for the program to scan through the 2-D map of its area.  I first modeled
microscopic Fresnel zones this way in Excel by using a 100 by 100 array
spreadsheet page to define my "amplitude map".  It became a
"picture" of my Fresnel optic displaying either a 1 or a 0
depending on whether that cell (pixel) contributed or not.  To truly define
resolution one would have to repeat this type of computation for each
location in the image plane surrounding the center of the "Airy"
disk in order to map out the resultant image.  For symetrical systems only
calculating along one radial axis is neaded due to symetry but for spiders
or localized "chips" a "mapping" method would be
required.

Unless you are truly differential equation, high calculus, Fourier
Transform fluent, this to me is the easy (realtively speaking) way to
define a "general" solution to analyzing a whole variety of
aperture types and unique conditions.

Regards,

Kurt Sidor
Mechanical Engineer
Dynamics Research Corp.
Encoder Division

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