Re: [ATM] [atm_free] Detecting Astig in Ronchi images

["Mel Bartels" <mbartels@bbastrodesigns.com>]

> I'm trying to help David Davis identify astig in
> ronchi images.  Can any of you see signs of astig in
> these images?   They were taken every .05 inches
> starting about .2 inside ROC.


Yes, bad 'stig in the 30-70% zones, and some 'stig in the other zones.


> If you can identify what it is that tells you.  Can
> you also estimate the major axis and/or the magnitude?


You didn't state the grating frequency, so it becomes even more of a ball
park guess, but I'd say in the neighborhood of 1 wave of 'stig.

As to the major axis, that's hard to say without rotating the mirror and
comparing, but I'll guess an upper left to lower right major axis.



Mel Bartels
 

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