Huyghenian

2 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Huyghenian \Huy*ghe"ni*an\, a.
     Pertaining to, or invented by, Christian Huyghens, a Dutch
     astronomer of the seventeenth century; as, the Huyghenian
     telescope.
     [1913 Webster]
  


     {Huyghenian eyepiece}See under {Eyepiece}.
        [1913 Webster]

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  eyepiece \eye"piece`\ eye-piece \eye"-piece`\, n. (Opt.)
     The lens, or combination of lenses, at the eye end of a
     microscope, telescope or other optical instrument, through
     which the image formed by the mirror or object glass is
     viewed.
  
     Syn: ocular.
          [1913 Webster]
  
     {Collimating eyepiece}. See under {Collimate}.
  
     {Negative}, or {Huyghenian}, {eyepiece}, an eyepiece
        consisting of two plano-convex lenses with their curved
        surfaces turned toward the object glass, and separated
        from each other by about half the sum of their focal
        distances, the image viewed by the eye being formed
        between the two lenses. it was devised by Huyghens, who
        applied it to the telescope. Campani applied it to the
        microscope, whence it is sometimes called {Campani's
        eyepiece}.
  
     {Positive eyepiece}, an eyepiece consisting of two
        plano-convex lenses placed with their curved surfaces
        toward each other, and separated by a distance somewhat
        less than the focal distance of the one nearest eye, the
        image of the object viewed being beyond both lenses; --
        called also, from the name of the inventor, {Ramsden's
        eyepiece}.
  
     {terrestrial}, or {Erecting eyepiece}, an eyepiece used in
        telescopes for viewing terrestrial objects, consisting of
        three, or usually four, lenses, so arranged as to present
        the image of the object viewed in an erect position.
        [1913 Webster]