| laser disk |
see "optical disk." |
| lead glass |
a brilliant optical glass containing lead oxide, characterized by high refraction and low dispersion; flint glass; crystal. |
| mirage |
an optical effect, often occurring in the desert or on hot pavement, in which light distorted by air masses of different temperatures creates the illusion of water and sometimes inverts distant objects. [1/2 definitions] |
| neodymium |
a rare-earth metallic chemical element that has sixty protons in each nucleus and that occurs most frequently as a trivalent ion in salts and minerals, used esp. in coloring high-quality optical glass. (symbol: Nd) |
| objective |
in optical instruments such as telescopes and microscopes, the lens closest to the object being observed. [1/7 definitions] |
| ocular |
an eyepiece, as in an optical instrument. [1/3 definitions] |
| op art |
a style of abstract, usu. hard-edged art in which forms, spaces, and colors are deliberately arranged to produce optical ambiguities and illusions. |
| optic |
of or concerning the science of sight and the properties of light; optical. [1/3 definitions] |
| optical disk |
the place on the eye's retina to which the optical nerve is attached. [1/2 definitions] |
| optician |
a person who sells or manufactures eyeglasses, contact lenses, or other optical devices. . |
| periscope |
a tubular optical instrument fitted with mirrors and prisms so as to allow one to see what is not in the direct line of sight or what is obstructed from sight. |
| polarimeter |
an instrument for measuring the optical activity or refractive index of substances, esp. liquids. [1/2 definitions] |
| reflecting telescope |
an optical telescope that uses mirrors rather than lenses to focus light rays. (Cf. refracting telescope.) |
| refracting telescope |
an optical telescope that uses lenses rather than mirrors to focus light rays. (Cf. reflecting telescope.) |
| resolving power |
the ability of an optical system to yield separate images of close points. [1/2 definitions] |
| reticule |
a network of fine lines, wires, or the like placed in the eyepiece of an optical instrument; reticle. [1/2 definitions] |
| saccharimeter |
an optical instrument that measures the concentration of sugar in a solution. |
| Schmidt system |
an optical system used in telescopes consisting of a spherical concave mirror with a correcting plate that reduces aberrations. |
| spectroscope |
an optical instrument that enables examination, measurement, or recording of a spectrum by rendering its component electromagnetic waves, as of light or radiation, distinct and visible. |
| speculum |
one of the mirrors in a reflecting telescope or other optical instrument. [1/3 definitions] |
| telescope |
an optical instrument, usu. cylindrical, that employs lenses and sometimes mirrors to enlarge the images of distant objects, esp. those in outer space. [1/7 definitions] |