a. Applied to a modification of the Gregorian reflecting telescope suggested in 1672 by M. Cassegrain.
1813. Kater, in Phil. Trans., No. 206 (title), On the light of the Cassegrainian Telescope, compared with that of the Gregorian.
1831. Brewster, Optics, xlii. 352. The Cassegrainian telescope … differs from the Gregorian only in having its small speculum … convex instead of concave.
