Cas′se•grain tel′escope(kas′ə grān′),USA pronunciation[Astron.]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. Also called Cas•se•grain′i•an tel′escope(kas′ə grā′nē ən).USA pronunciation
named after north, northern. Cassegrain, 17th-century French scientist, its inventor 1805–15