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Huygens eyepiece

American  

noun

Optics.

  1. an eyepiece consisting of two plano-convex lenses, the plane sides of which both face the eye.

Huygens' eyepiece British  
/ ˈhaɪɡənz /

noun

  1. physics a telescope eyepiece consisting of two planoconvex lenses separated by a distance equal to half the sum of their focal lengths, which are in the ratio of three to one, and oriented so that their curved surfaces face the incident light

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of Huygens eyepiece

First recorded in 1830–40; named after C. Huygens

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The Huygens eyepiece consists of two plano-convex lenses whose focal lengths are in the ratio of three to one.

From Pleasures of the telescope An Illustrated Guide for Amateur Astronomers and a Popular Description of the Chief Wonders of the Heavens for General Readers by Serviss, Garrett Putman

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.