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

Of or relating to an optical system corrected for → distortion.

→ ortho-; → -scopic.

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.