| Heliostat (n.) An instrument consisting of a mirror moved by clockwork, by which a sunbeam is made apparently stationary, by being steadily directed to one spot during the whole of its diurnal period; also, a geodetic heliotrope. Thesaurus Entries Cassegrainian telescope, Newtonian telescope, OAO, OSO, Texas tower, astronomical observatory, astronomical telescope, beacon, belvedere, bleachers, bridge, coelostat, conning tower, coronagraph, coronograph, gallery, gazebo, grandstand, heliostat, lighthouse, lookout, loophole, observation post, orrery, outlook, overlook, peanut gallery, peephole, pharos, planetarium, radar telescope, radio observatory, radio telescope, reflector, refractor, ringside, ringside seat, sighthole, spectrograph, spectroheliograph, spectrohelioscope, spectroscope, telescope, top gallery, tower, watchtower |