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An optical system consisting of a concave spherical mirror with a transparent lens, resembling a plate of glass, located at its center of curvature, used in reflecting telescopes to offset spherical aberration and coma.
[After Bernhard Voldemar Schmidt (1879-1935), Estonian-born German optical scientist.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.