An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

A → lens system, also known as an → ocular, used to → magnify the → image formed by the → objective of a → telescope.

→ eye; → piece.

Cašmi "ocular," adj. of cašm→ eye + -i adj. suffix.

The first achromatic eyepiece consisting of a convex lens and a plano-convex lens. The convex surfaces are turned toward one another.

Named after the inventor Carl Kellner (1826-1855), a German engineer and optician; → eyepiece

A telescopic eyepiece that produces a wide field of view (between 40° and 50°). The eyepiece consists of a single element lens that is normally plano-convex, and a cemented triplet that is usually symmetrical.

→ orthoscopic; → eyepiece.

An eyepiece consisting of two planoconvex lenses of the same focal length, placed with the convex sides facing each other and with a separation between the lenses of about two-thirds of the focal length of each.

Named after Jesse Ramsden (1735-1800), English maker of astronomical instruments; → eyepiece.