Also found in: Dictionary, Thesaurus, Wikipedia.
a reflector designed by W. Herschel (1789), in which a concave parabolic mirror is inclined toward an incoming pencil of rays in such a way that the image is formed outside this pencil. The Herschelian telescope does not screen the rays, but it has aberrations. A similar system was proposed by M. V. Lomonosov in 1762.
N. N. MIKHEL’SON