Cassegrain telescope

[ kas-uh-greyn ]
/ ˈkæs əˌgreɪn /

noun Astronomy.

a reflecting telescope in which the light, passing through a central opening in the primary mirror, is brought into focus a short distance behind it by a secondary mirror.

Origin of Cassegrain telescope

1805–15; named after N. Cassegrain, 17th-century French scientist, its inventor
Also called Cas·se·grain·i·an tel·escope [kas-uh-grey-nee-uh n] /ˌkæs əˈgreɪ ni ən/. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

British Dictionary definitions for cassegrain telescope

Cassegrain telescope
/ (ˈkæsɪˌɡreɪn) /


an astronomical reflecting telescope in which incident light is reflected from a large concave paraboloid mirror onto a smaller convex hyperboloid mirror and then back through a hole in the concave mirror to form the image

Word Origin for Cassegrain telescope

C19: named after N. Cassegrain, 17th-century French scientist who invented it
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