Resolution Limits
(a) Monochromatic light passed through a small circular aperture produces this diffraction pattern. (b) Two point light sources that are close to one another produce overlapping images because of diffraction. (c) If they are closer together, they cannot be resolved or distinguished.
Source
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"OpenStax College, Limits of Resolution: The Rayleigh Criterion. January 11, 2013."
http://cnx.org/content/m42517/latest/
OpenStax CNX
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