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