A design of eyepiece that usually consists of a cemented triplet field lens and a planoconvex eye lens. This combination provides good correction for chromatic aberration, spherical aberration, coma (see Coma, Optical), and distortion, at reasonable cost. Orthoscopic eyepieces have a field of view of 35–50° and good eye relief. The design was introduced in 1880 by the German physicist Ernst Karl Abbe (1840–1905).
Subjects: Astronomy and Astrophysics.