[ATM] preferred ronchi grating lpi?

[glenn.forney at nist.gov (Glenn Forney)]

I have a superficial understanding of the ronchi test and would like to understand it better.  I see ronchi gratings with 100 lines per inch, 133 lines per inch and even higher densities.  Is bigger better or is there a preferred grating density for a given mirror size or focal length?
glenn

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Glenn Forney
National Institute of Standards and Technology
100 Bureau Drive, Stop 8663
Gaithersburg MD 20899-8663

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