telescope, newtonian telescope, optical telescope, astronomical telescope, observatory, retroreflector, camera obscura, celestial sphere, spectroscope, zoetrope, stereoscopes, armillary sphere, armillary, gnomon, refractor, arcsecond, planetarium, syrtis major, trifid, cuboid, harlow shapley, omega centauri, parabolic mirror, epsilon aurigae, polarimeter, sundials, lunette, eyepieces, interferometer, diffractometer, tetrahedron, geodesic, convex lens, horsehead nebula, ursa minor, glassless, sauropod dinosaur, pallasite, photometer, smos, earthshine, diplodocus, borealis, tycho brahe, deimos, collinear, binocular, edwin hubble, trilobite, refracting, celestial mechanics, chitons, ellipsoidal, iris diaphragm, diameter, astronomy, eclipsing binary, proxima centauri, pinhole camera, fresnel, schlieren, unpolarized, andromeda galaxy, monoceros, small magellanic cloud, gigantea, gyrocompass, astronomer, astron, quasicrystal, photogram, stereographic, spectro, spherical, reredos, radiometer, heinrich hertz, niepce, dormered, circinus, gibbous, klystron, astrometry, quatrefoil, hubble, coma berenices, milky way galaxy, canes venatici, turtleback, prisms, polyhedron, spectrographic, conic, multispectral, dodecahedron, magellanic, blackbody, stegodon, ostracods, theodolite, scintillator, gimbals

field glass, galilean telescope, glass, spyglass

optical telescope