zenith tube

  1. a telescope mounted to point only at the zenith, used at some observatories for measuring time by the stars.

Origin of zenith tube

First recorded in 1830–40
  • Also called zenith telescope.

Words Nearby zenith tube

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use zenith tube in a sentence

  • He devised a reflex zenith tube, in which the zenith point was determined by reflection from a surface of mercury.

    History of Astronomy | George Forbes