[ATM] Re: FigureXP and Foucault test Analysis

[Andreas Reifke <andreas.reifke@web.de>]

Hi Jan,

>> I have used two programs to evaluate the foucault readings of the 12 inch
>> f/5 mirror I am making: FigureXP and Foucault Test Analysis. The last
>> program consistently evaluates the quality lower. Where, for instance,
>> figure XP calculates a P-V wavefront error of 1/6.32 lambda, FTA calculates
>> a wavefront error of 1/4.28 lambda. Does someone know the cause of the
>> difference and which program is correct?

one explanation for the difference could be that both programs are using different methods for calculating the effective zone radius. 
FigureXP uses Nils Olof-Carlin's method. In Foucault-Test-Analysis the default setting for calculating the effective zone radius is
the "traditional" method suggested by Texereau. But you can choose between the following methods in FTA:

- Texereau
- Nils Olof Carlin
- Couder

If you choose "Effective Zone Radius ==> Nils Olof Carlin" on the first window "mirror setup" you should obtain nearly the same 
results for your mirror as in FigureXP. If that doesn't help: Can you e-mail me your mirror-file, please ?

Regards,

Andreas Reifke
www.foucault-test-analysis.de

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