Adjacent Words

Aplanatic definitions

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Webster's 1828 Dictionary

APLANAT'IC, a. [Gr. to wander.]
An aplanatic telescope is one which entirely corrects the aberration of the rays of light. It is thus distinguished from the achromatic, which only partially corrects the aberration.

WordNet (r) 3.0 (2005)

adj
1: free from or corrected for spherical aberration; "an aplanatic mirror"

Merriam Webster's

adjective Etymology: a- + Greek planasthai to wander — more at planet Date: 1794 free from or corrected for spherical aberration <an aplanatic lens>

Oxford Reference Dictionary

adj. (of a reflecting or refracting surface) free from spherical aberration. Etymology: Gk aplanetos free from error f. a- not + planao wander

Webster's 1913 Dictionary

Aplanatic Ap`la*nat"ic, a. [Gr. 'a priv. + ? disposed to wander, wandering, ? to wander.] (Opt.) Having two or more parts of different curvatures, so combined as to remove spherical aberration; -- said of a lens. Aplanatic focus of a lens (Opt.), the point or focus from which rays diverging pass the lens without spherical aberration. In certain forms of lenses there are two such foci; and it is by taking advantage of this fact that the best aplanatic object glasses of microscopes are constructed.