See under telescope (def 1).
an optical instrument for making distant objects appear larger and therefore nearer. One of the two principal forms (refracting telescope) consists essentially of an objective lens set into one end of a tube and an adjustable eyepiece or combination of lenses set into the other end of a tube that slides into the first and through which the enlarged object is viewed directly; the other form (reflecting telescope) has a concave mirror that gathers light from the object and focuses it into an adjustable eyepiece or combination of lenses through which the reflection of the object is enlarged and viewed.
Compare radio telescope.
(initial capital letter) Astronomy. the constellation Telescopium.
consisting of parts that fit and slide one within another.
verb (used with object), telescoped, telescoping.
to force together, one into another, or force into something else, in the manner of the sliding tubes of a jointed telescope.
to shorten or condense; compress:
to telescope the events of five hundred years into one history lecture.
verb (used without object), telescoped, telescoping.
to slide together, or into something else, in the manner of the tubes of a jointed telescope.
to be driven one into another, as railroad cars in a collision.
to be or become shortened or condensed.
a type of telescope in which the image is formed by a set of lenses Also called refractor Compare reflecting telescope
an optical instrument for making distant objects appear larger and brighter by use of a combination of lenses (refracting telescope) or lenses and curved mirrors (reflecting telescope) See also terrestrial telescope, astronomical telescope, Cassegrain telescope, Galilean telescope, Newtonian telescope
any instrument, such as a radio telescope, for collecting, focusing, and detecting electromagnetic radiation from space
to crush together or be crushed together, as in a collision: the front of the car was telescoped by the impact
to fit together like a set of cylinders that slide into one another, thus allowing extension and shortening
to make or become smaller or shorter: the novel was telescoped into a short play
See under telescope.
An arrangement of lenses, mirrors, or both that collects visible light, allowing direct observation or photographic recording of distant objects. ◇ A refracting telescope uses lenses to focus light to produce a magnified image. Compound lenses are used to avoid distortions such as spherical and chromatic aberrations. ◇ A reflecting telescope uses mirrors to view celestial objects at high levels of magnification. Most large optical telescopes are reflecting telescopes because very large mirrors, which are necessary to maximize the amount of light received by the telescope, are easier to build than very large lenses.
Any of various devices, such as a radio telescope, used to detect and observe distant objects by collecting radiation other than visible light.
A device used by astronomers to magnify images or collect more light from distant objects by gathering and concentrating radiation. The most familiar kind of telescope is the optical telescope, which collects radiation in the form of visible light. It may work by reflection, with a bowl-shaped mirror at its base, or by refraction, with a system of lenses. Other kinds of telescopes collect other kinds of radiation; there are radio telescopes (which collect radio waves), x-ray telescopes, and infrared telescopes. Radio and optical telescopes may be situated on the Earth, since the Earth’s atmosphere allows light and radio waves through but absorbs radiation from several other regions of the electromagnetic spectrum. X-ray telescopes are placed in space.
noun 1. Physics. the change of direction of a ray of light, sound, heat, or the like, in passing obliquely from one medium into another in which its wave velocity is different. 2. Ophthalmology. the ability of the eye to refract light that enters it so as to form an image on the retina. the […]
refractionist re·frac·tion·ist (rĭ-frāk’shə-nĭst) n. A person trained to measure the refraction of the eye and to determine the proper corrective lenses.
adjective 1. of or relating to refraction. 2. Also, refractile. having power to refract. adjective 1. of or concerned with refraction 2. (of a material or substance) capable of causing refraction
noun, Optics. 1. index of refraction. refractive index noun 1. (physics) a measure of the extent to which radiation is refracted on passing through the interface between two media. It is the ratio of the sine of the angle of incidence to the sine of the angle of refraction, which can be shown to be […]