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3 definitions found
 for Gregorian telescope
From The Collaborative International Dictionary of English v.0.48 :

  Gregorian \Gre*go"ri*an\, a. [NL. Gregorianus, fr. Gregorius
     Gregory, Gr. ?: cf. F. gr['e]gorien.]
     Pertaining to, or originated by, some person named Gregory,
     especially one of the popes of that name.
     [1913 Webster]
  
     Gregorian calendar, the calendar as reformed by Pope
        Gregory XIII. in 1582, including the method of adjusting
        the leap years so as to harmonize the civil year with the
        solar, and also the regulation of the time of Easter and
        the movable feasts by means of epochs. See Gregorian
        year (below).
  
     Gregorian chant (Mus.), plain song, or canto fermo, a kind
        of unisonous music, according to the eight celebrated
        church modes, as arranged and prescribed by Pope Gregory
        I. (called "the Great") in the 6th century.
  
     Gregorian modes, the musical scales ordained by Pope
        Gregory the Great, and named after the ancient Greek
        scales, as Dorian, Lydian, etc.
  
     Gregorian telescope (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.
  
     Gregorian year, the year as now reckoned according to the
        Gregorian calendar. Thus, every year, of the current
        reckoning, which is divisible by 4, except those divisible
        by 100 and not by 400, has 366 days; all other years have
        365 days. See Bissextile, and Note under Style, n., 7.
        [1913 Webster]

From The Collaborative International Dictionary of English v.0.48 :

  Telescope \Tel"e*scope\, n. [Gr. ? viewing afar, farseeing; ?
     far, far off + ? a watcher, akin to ? to view: cf. F.
     t['e]lescope. See Telegraph, and -scope.]
     An optical instrument used in viewing distant objects, as the
     heavenly bodies.
     [1913 Webster]
  
     Note: A telescope assists the eye chiefly in two ways; first,
           by enlarging the visual angle under which a distant
           object is seen, and thus magnifying that object; and,
           secondly, by collecting, and conveying to the eye, a
           larger beam of light than would enter the naked organ,
           thus rendering objects distinct and visible which would
           otherwise be indistinct and or invisible. Its essential
           parts are the object glass, or concave mirror, which
           collects the beam of light, and forms an image of the
           object, and the eyeglass, which is a microscope, by
           which the image is magnified.
           [1913 Webster]
  
     Achromatic telescope. See under Achromatic.
  
     Aplanatic telescope, a telescope having an aplanatic
        eyepiece.
  
     Astronomical telescope, 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.
  
     Cassegrainian telescope, 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.
  
     Dialytic telescope. See under Dialytic.
  
     Equatorial telescope. See the Note under Equatorial.
  
     Galilean telescope, 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.
  
     Gregorian telescope, a form of reflecting telescope. See
        under Gregorian.
  
     Herschelian telescope, 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.
  
     Newtonian telescope, a form of reflecting telescope. See
        under Newtonian.
  
     Photographic telescope, a telescope specially constructed
        to make photographs of the heavenly bodies.
  
     Prism telescope. See Teinoscope.
  
     Reflecting telescope, 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.
  
     Refracting telescope, a telescope in which the image is
        formed by refraction through an object glass.
  
     Telescope carp (Zool.), the telescope fish.
  
     Telescope fish (Zool.), a monstrous variety of the goldfish
        having very protuberant eyes.
  
     Telescope fly (Zool.), 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.
  
     Telescope shell (Zool.), an elongated gastropod ({Cerithium
        telescopium) having numerous flattened whorls.
  
     Telescope sight (Firearms), a slender telescope attached to
        the barrel, having cross wires in the eyepiece and used as
        a sight.
  
     Terrestrial telescope, a telescope whose eyepiece has one
        or two lenses more than the astronomical, for the purpose
        of inverting the image, and exhibiting objects erect.
        [1913 Webster]

From WordNet (r) 3.0 (2006) :

  Gregorian telescope
      n 1: 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 [syn: Cassegrainian telescope, Gregorian
           telescope]

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