eyepiece eye"piece` eye-piece eye"-piece`, n. (Opt.) The lens, or combination of lenses, at the eye end of a microscope, telescope or other optical instrument, through which the image formed by the mirror or object glass is viewed.

Syn: ocular. [1913 Webster]

{Collimating eyepiece}. See under {Collimate}.

{Negative}, or {Huyghenian}, {eyepiece}, an eyepiece consisting of two plano-convex lenses with their curved surfaces turned toward the object glass, and separated from each other by about half the sum of their focal distances, the image viewed by the eye being formed between the two lenses. it was devised by Huyghens, who applied it to the telescope. Campani applied it to the microscope, whence it is sometimes called {Campani's eyepiece}.

{Positive eyepiece}, an eyepiece consisting of two plano-convex lenses placed with their curved surfaces toward each other, and separated by a distance somewhat less than the focal distance of the one nearest eye, the image of the object viewed being beyond both lenses; -- called also, from the name of the inventor, {Ramsden's eyepiece}.

{terrestrial}, or {Erecting eyepiece}, an eyepiece used in telescopes for viewing terrestrial objects, consisting of three, or usually four, lenses, so arranged as to present the image of the object viewed in an erect position. [1913 Webster]

The Collaborative International Dictionary of English. 2000.


Look at other dictionaries:

  • Terrestrial — Ter*res tri*al, a. [L. terrestris, from terra the earth. See {Terrace}.] 1. Of or pertaining to the earth; existing on the earth; earthly; as, terrestrial animals. Bodies terrestrial. 1 Cor. xv. 40. [1913 Webster] 2. Representing, or consisting… …   The Collaborative International Dictionary of English

  • Terrestrial — refers to things having to do with the land or the Earth.Related terms* Extra Terrestrial, the sloven hore next door * Terrestrial animal, an animal that lives on the land, as opposed to in water, air, or in the trees * Terrestrial plant, a plant …   Wikipedia

  • terrestrial — ter‧res‧tri‧al [təˈrestriəl] adjective TELECOMMUNICATIONS terrestrial televisions, networks etc operate on earth using radio waves, and not from a satellite: • terrestrial television channels * * * terrestrial UK US /təˈrestriəl/ adjective ►… …   Financial and business terms

  • terrestrial — [tə res′trē əl] adj. [ME terrestrialle < L terrestris < terra,TERRA] 1. of this world; worldly; earthly; mundane 2. of, constituting, or representing the earth [a terrestrial globe] 3. consisting of land as distinguished from water 4.… …   English World dictionary

  • Terrestrial — Ter*res tri*al, n. An inhabitant of the earth. [1913 Webster] …   The Collaborative International Dictionary of English

  • terrestrial — index mundane Burton s Legal Thesaurus. William C. Burton. 2006 …   Law dictionary

  • terrestrial — early 15c., from L. terrestris earthly, from terra earth (see TERRAIN (Cf. terrain)). Originally opposed to celestial; natural history sense of living on land is attested from 1630s. The noun meaning a human being, a mortal is recorded from 1590s …   Etymology dictionary

  • terrestrial — *earthly, earthy, mundane, worldly, sublunary Antonyms: celestial …   New Dictionary of Synonyms

  • terrestrial — [adj] earthly earthbound, earthlike, earthy, global, mundane, physical, profane, prosaic, secular, sublunary, subsolar, telluric, temporal, terrene, uncelestial, unspiritual, worldly; concept 536 Ant. cosmic, heavenly, otherworldly …   New thesaurus

  • terrestrial — ► ADJECTIVE 1) of, on, or relating to the earth or dry land. 2) (of an animal or plant) living on or in the ground. 3) (of television broadcasting) using ground based equipment rather than a satellite. ► NOUN ▪ an inhabitant of the earth.… …   English terms dictionary

  • terrestrial — adjective Etymology: Middle English, from Latin terrestris, from terra earth more at terrace Date: 15th century 1. a. of or relating to the earth or its inhabitants < terrestrial magnetism > b. mundane in scope or character ; prosaic 2. a …   New Collegiate Dictionary

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