from The Century Dictionary.
- noun An astronomical instrument for measuring with great accuracy the zenith-distances of stars which pass near the zenith.
Sorry, no etymologies found.
In the same apartment is the famous zenith-sector, twelve feet in length, with which Dr. Bradley, at Wanstead, and at Kew, made those observations which led to the discovery of the aberration and nutation: here also is Dr. Hooke's reflecting telescope, and three telescopes by Harrison.
Ramsden, all of whom, however, gave the preference to the old-fashioned mural quadrant and zenith-sector over the entire circle, which Römer had already found the advantage of employing.