telescope

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Related to Schmidt telescope: Schmidt camera

tel·e·scope

(tel'ĕ-skōp),
1. An optic instrument used to visualize or photograph distant or out-of-view objects through magnification of the image or angulation of the reflected light. In medicine, usually combined with endoscopy.
2. Enclosure such that smaller segments collapse into larger.
[tele- + G. skopeō, to view]

telescope 

An optical instrument for magnifying the apparent size of distant objects. It consists, in principle, of two lenses: (1) the objective, being a positive lens which forms a real inverted image of the distant object; (2) the eyepiece through which the observer views a magnified image of that formed by the objective. The eyepiece may be either positive (astronomical or Kepler telescope) or negative (galilean telescope). The magnification M of a telescope is given by the following formula
M = fo/fe
= Do/Dewhere fo is the second focal length of the objective, fe the first focal length of the eyepiece, and Do and De are the diameters of the entrance and exit pupils of the telescope (approximately equal to the diameters of the objective lens and the eyepiece).There are also some telescopes that do not use a lens (or lens system) as objective, as these are difficult to produce if large apertures and minimum aberrations are required. These telescopes use a concave mirror (usually parabolic) as the objective. They are called reflecting telescopes. Light from a distant object is collected by the large concave mirror and reflected onto a small mirror (positive in the Cassegrain telescope and negative in the gregorian telescope). This mirror is located on the optical axis and light is then transmitted through a central hole in the concave mirror onto the eyepiece. In the newtonian telescope the light collected by the large concave mirror is reflected onto a small plane mirror at a 45º angle to the optical axis, and transmitted to the eyepiece, which is at right angles to the optical axis (Fig. T1). See binoculars; eyepiece; telescopic magnification; objective.
astronomical telescope See telescope.
bioptic telescope A system of lenses forming a galilean or Kepler telescope which is mounted high on a plastic spectacle or carrier lens with the distance correction, so as to allow the patient to look through either the telescope, or below, by moving his or her head. It is used to magnify distant objects for patients with low vision. Syn. bioptic position telescope.
Cassegrain telescope See telescope.
Dutch telescope See galilean telescope.
galilean telescope A simple optical system that allows observation of far objects with a low magnification and without image inversion. It consists of a convex lens, which acts as the objective, and a concave lens as the eyepiece. Magnification of such a telescope rarely exceeds ✕ 5. This optical system is used in opera glasses and as a low vision aid (Fig. T1). Syn. Dutch telescope. See binoculars; minification.
gregorian telescope; Kepler telescope; newtonian telescope See telescope.
reflecting telescope A telescope that uses a concave mirror as the objective.
refracting telescope A telescope that uses a positive lens system as the objective.
reverse telescope See visual expander field.
terrestrial telescope A telescope that provides an erect image of a distant object. The image is usually erected by means of a lens system placed between the objective and the eyepiece. It does, however, make the terrestrial telescope relatively longer than an astronomical telescope. See binoculars; erector.
Fig. T1 Telescopes: A, galilean; B, Keplerenlarge picture
Fig. T1 Telescopes: A, galilean; B, Kepler
References in periodicals archive ?
Lawrence, JPL, reported the discovery of another 18th mag comet on CCD images taken with the 1.2m Schmidt telescope at Palomar in the course of the NEAT program; their discovery image on Aug 28.41 showed a central nebulosity of diameter about 3" and a tail about 10" long toward the WSW.
In March 1950, it was reported that the German optical firm Schott & Genossen could make a disc of a special optical glass which was able to transmit ultra-violet light, something that no other large Schmidt telescope was then capable of doing.
The photo was taken by Jet Propulsion Laboratory scientist Eleanor Helin, using Palomar's 46-centimeter Schmidt telescope. The two comets appear less than 2 degress apart in the sky as seen from earth, about four times the diameter of the moon.
He spotted it on images taken with the 20-inch (0.5-meter) Uppsala Schmidt telescope at Siding Spring Observatory, pictured.
Kepler's 1-meter Schmidt telescope, with a 95-megapixel array of CCDs, will stare for four years at a region of sky between Vega and Deneb.
That's especially true in Markarian's Chain, the region shown in this composite made with the 48-inch (1.2-meter) Oschin Schmidt telescope atop Palomar Mountain in Southern California.
The object was magnitude 19.3 when discovered last September 14th with the 0.68-meter (27-inch) Schmidt telescope of the Catalina Sky Survey in Arizona, and it never got much brighter.
In addition, Evans found five supernovae on photographs: four on United Kingdom Schmidt Telescope plates as part of a professional-amateur search effort in 1996, and one on ESO Red Survey plates.
Secondly using complex, high-quality, professionally-managed Schmidt telescopes, widely known as "Baker-Nunn" cameras, (2) (see also MNASSA Vol 71 Nos 5 & 6 June 2012).
Billed as aplanatic Schmidt telescopes, the EdgeHD series represents the first major redesign of the Schmidt-Cassegrain optical system that Celestron introduced in the 1960s.