Aplanat

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Related to aplanatic: aplanatic Gregorian, aplanatic lens

Aplanat

 

a photographic objective with an optical system consisting of two achromatic lenses placed symmetrically about the diaphragm. The aplanat is free from spherical aberration, chromatic aberration, and distortion; but astigmatism, though severely attenuated, remains present. Because of its simplicity of design and loose mounting requirements, the aplanat lends itself readily to use as a universal lens with a relative aperture from f/8—rarely f/5 (for portrait work and group photographs)—to f/16 (as a wide-angle lens). With the appearance of anastigmats, aplanats lost their significance and are now produced in small quantities.

REFERENCE

Lapauri, A. A. Fotograficheskaia optika. Moscow, 1955.
References in periodicals archive ?
Aplanatic lenses are used in excimer laser beam handling and steering, high energy and UV Nd:YAG machining applications, fiber laser micromachining applications, laser material ablation, UV imaging spectroscopy, and UV microscopy.
Contract awarded for purchase three aplanatic tonometers for teaching of the school of medical technology common entrance and ophthalmology,
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Collaborating with French optical designer Henri Chretien, Ritchey showed that a Cassegrain-style reflector with two approximately hyperboloidal mirrors would be aplanatic (free of coma) and thus able to cover large photographic plates from corner to corner with beautifully round stars.
Optics won, and we unscrewed the machined lens cap to reveal the aplanatic, three-element objective, which has a central element made of ED glass.