telescope : Idioms & Phrases

• . See under Achromatic.

Webster 1913

• one in which the chromatic aberration is corrected, usually by means of a compound or achromatic object glass, and which gives images free from extraneous color.

Webster 1913

• a telescope having an aplanatic eyepiece.

Webster 1913

• noun any telescope designed to collect and record electromagnetic radiation from cosmic sources
  

WordNet

• a telescope which has a simple eyepiece so constructed or used as not to reverse the image formed by the object glass, and consequently exhibits objects inverted, which is not a hindrance in astronomical observations.

Webster 1913

• the straight line with which coincide the axes of the several lenses which compose it.

Webster 1913

• noun a reflecting telescope that has a paraboloidal primary mirror and a hyperboloidal secondary mirror; light is brought to a focus through an aperture in the center of the primary mirror
  Cassegrainian telescope.
  

WordNet

• a reflecting telescope invented by Cassegrain, which differs from the Gregorian only in having the secondary speculum convex instead of concave, and placed nearer the large speculum. The Cassegrainian represents objects inverted; the Gregorian, in their natural position. The Melbourne telescope (see Illust. under Reflecting telescope, below) is a Cassegrainian telescope.

Webster 1913

• noun a reflecting telescope so constructed that the light is led to a plate holder or spectrograph
  coude system.
  

WordNet

• an achromatic telescope in which the colored dispersion produced by a single object lens of crown glass is corrected by a smaller concave lens, or combination of lenses, of high dispersive power, placed at a distance in the narrower part of the converging cone of rays, usually near the middle of the tube.

Webster 1913

• . See the Note under Equatorial.

Webster 1913

• the distance of the image of an object from the object glass.

Webster 1913

• noun a type of refracting telescope that is no longer used in astronomy
  

WordNet

• a refracting telescope in which the eyeglass is a concave instead of a convex lens, as in the common opera glass. This was the construction originally adopted by Galileo, the inventor of the instrument. It exhibits the objects erect, that is, in their natural positions.

Webster 1913

• noun a reflecting telescope that has a paraboloidal primary mirror and a hyperboloidal secondary mirror; light is brought to a focus through an aperture in the center of the primary mirror
  Cassegrainian telescope.
  

WordNet

• (Opt.), a form of reflecting telescope, named from Prof. James Gregory, of Edinburgh, who perfected it in 1663. A small concave mirror in the axis of this telescope, having its focus coincident with that of the large reflector, transmits the light received from the latter back through a hole in its center to the eyepiece placed behind it.

Webster 1913

• noun a reflecting telescope with the mirror slightly tilted to throw the image to the side where it can be viewed
  off-axis reflector.
  

WordNet

• a reflecting telescope of the form invented by Sir William Herschel, in which only one speculum is employed, by means of which an image of the object is formed near one side of the open end of the tube, and to this the eyeglass is applied directly.

Webster 1913

• noun reflecting telescope in which the aberration of the concave mirror is reduced by a meniscus lens
  

WordNet

• noun reflecting telescope in which the image is viewed through an eyepiece perpendicular to main axis
  Newtonian reflector.
  

WordNet

• (Astron.), a reflecting telescope, in which rays from the large speculum are received by a plane mirror placed diagonally in the axis, and near the open end of the tube, and thrown at right angles toward one side of the tube, where the image is formed and viewed through the eyeplace.

Webster 1913

• noun an astronomical telescope designed to collect and record light from cosmic sources
  

WordNet

• a telescope specially constructed to make photographs of the heavenly bodies.

Webster 1913

• . See Teinoscope.

Webster 1913

• noun astronomical telescope that picks up electromagnetic radiations in the radio-frequency range from extraterrestrial sources
  radio reflector.
  

WordNet

• noun optical telescope consisting of a large concave mirror that produces an image that is magnified by the eyepiece
  reflector.
  
  • Isaac Newton invented the reflecting telescope in 1668

WordNet

• a telescope in which the image is formed by a speculum or mirror (or usually by two speculums, a large one at the lower end of the telescope, and the smaller one near the open end) instead of an object glass. See Gregorian, Cassegrainian, Herschelian, ∧ Newtonian, telescopes, above.

Webster 1913

• noun optical telescope that has a large convex lens that produces an image that is viewed through the eyepiece
  

WordNet

• a telescope in which the image is formed by refraction through an object glass.

Webster 1913

• noun reflecting telescope that has plate that corrects for aberration so a wide area of sky can be photographed
  Schmidt camera.
  

WordNet

• (Dialing), an instrument consisting of a horizontal dial, with a telescope attached to it, used for determining the time, whether of day or night.

Webster 1913

• noun a telescope designed to make observations of the sun
  

WordNet

• (Zoöl.), the telescope fish.

Webster 1913

• (Zoöl.), a monstrous variety of the goldfish having very protuberant eyes.

Webster 1913

• (Zoöl.), any two-winged fly of the genus Diopsis, native of Africa and Asia. The telescope flies are remarkable for having the eyes raised on very long stalks.

Webster 1913

• (Zoöl.), an elongated gastropod (Cerithium telescopium) having numerous flattened whorls.

Webster 1913

• noun gunsight consisting of a telescope on a firearm for use as a sight
  telescopic sight.
  

WordNet

• (Firearms), a slender telescope attached to the barrel, having cross wires in the eyepiece and used as a sight.

Webster 1913

• a telescope whose eyepiece has one or two lenses more than the astronomical, for the purpose of inverting the image, and exhibiting objects erect.

Webster 1913

• (Geodesy), a telescope specially designed for determining the latitude by means of any two stars which pass the meridian about the same time, and at nearly equal distances from the zenith, but on opposite sides of it. It turns both on a vertical and a horizontal axis, is provided with a graduated vertical semicircle, and a level for setting it to a given zenith distance, and with a micrometer for measuring the difference of the zenith distances of the two stars.

Webster 1913