日光反射装置
Heliostat \He"li*o*stat\, n. [Helio- + Gr. ? placed, standing, fr. ? to place, stand: cf. F. h['e]liostate.] 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.