zenith-telescopehttp://www.oed.com/dictionary/zenith-telescope_n%3Ftab%3Dmeaning_and_usezenith telescope, n.
Revised 2018

zenith telescopenoun

  1. 1803–
    An astronomical telescope designed to point vertically up to the vicinity of the zenith, used in the precise determination of star positions, astronomical latitude, and the orientation of the earth's poles.
    1. 1803
      The principal instruments for a fixed observatory, are..a fixed zenith telescope, and a night telescope.
      T. Cavallo, Elements Nat. or Exper. Philosophy vol. IV. 268
    2. 1938
      In 1910..an order was given Mr. Gaertner for the construction of a Photographic Zenith Telescope.
      W. S. Downs, Encycl. Amer. Biography New Series 364/1
    3. 2007
      The only large telescope to date that uses a fixed mount..is the Large Zenith Telescope, and it uses a liquid mercury mirror.
      A. T. Tokunaga & R. Jedicke in L.-A. McFadden et al., Encycl. Solar Syst. (ed. 2) xxxix. 724/1

Originally published as part of the entry for zenith, n. & adj.

zenith, n. & adj. was revised in June 2018.