n. [ Helio- + -scope: cf. F. hélioscope. ] (Astron.) A telescope or instrument for viewing the sun without injury to the eyes, as through colored glasses, or with mirrors which reflect but a small portion of light. --
n. [ Helio- + Gr. &unr_; placed, standing, fr. &unr_; to place, stand: cf. F. héliostate. ] 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. [ 1913 Webster ]