eyepiece, loupe, photometer, monochromator, arcsecond, iris diaphragm, retroreflector, coronagraph, polarimeter, eclipsing binary, spectroscope, diffractometer, lenses, convex lens, newtonian telescope, collimator, galvanometer, imager, colorimeter, magnifications, reflector, photoluminescence, fresnel, photometry, emissivity, josephson junction, spherical aberration, collimating, bolometer, ophthalmoscope, microspectrophotometer, leica, infrared, refracting telescope, wavefront, photomultipliers, micrograph, photodetector, scintillator, enlarger, pyrometer, goniometer, epsilon aurigae, opto, sundog, zeiss, multispectral, telescope, absorption coefficient, photocells, chemiluminescence, cepheid variable, inclinometer, pinhole, spectro, optics, phototransistor, floor lamp, airglow, spectrographic, illuminance, deimos, binocular microscope, microbalance, diffraction grating, spectrophotometry, toric lens, horsehead nebula, penlight, cuvette, photolithographic, autofluorescence, flashgun, photoelectron, aperture, tauri, photomultiplier, stereographic, interferometer, astronomical telescope, photometric, toroid, luminosities, zoom lens, micrometre, spectrometer, bimetal, fisheye, subminiature, smoky quartz, celestial sphere, photodiodes, luminescence, watchcase, fluorescent dye, photogram, condenser microphone, lyrae, reflectometer, holograph, vignetting, octahedron, telescopes, lathe, theodolite, crusher, refractors, clipper, dredge, howitzer, lathes, sextant, aquarium, binoculars, boiler, burner, cooker, dryer, locomotive