Sunday, February 05, 2006

astigmatism - definition - optics

Definition: A defect/aberration in an optical system on account of which a point object does not produce a point image but instead produces two short lines at right angles to each other. A simple lens or spherical mirror always suffers from astigmatism if illuminated at an angle. Reducing the aperture of the system can prevent off-axis light entering the system.

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