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Old 24-11-2013, 12:10 PM
clive milne
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clive milne is offline
Join Date: May 2011
Location: Freo WA
Posts: 1,443
Originally Posted by Peter Ward View Post
Airy disk size (assuming perfect optics) is purely a function of F-ratio...
At the risk of sounding like pedant.. the airy disk size is proportional to f ratio and the wavelength of light concerned. It also decreases in size as you increase the size of the secondary obstruction.. if, however, the ca gets very large the amount of light concentrated in the airy disk reduces to the point where it is no longer meaningful to ignore the first diffraction ring as being a more sensible measure of the system performance..
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