from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An instrument designed to measure the brightness, relation, or apparent magnitude of stars.
from the GNU version of the Collaborative International Dictionary of English
- n. An instrument for comparing the relative amount of the light of stars.
from The Century Dictionary and Cyclopedia
- n. An instrument designed to measure the relation, brightness, or apparent magnitude of the stars.
"astrometer" in which an "artificial star," formed by the total reflection of moonlight from the base of a prism, served as a standard of comparison, he was able to estimate the lustre of the _natural_ stars examined by the distances at which the artificial object appeared equal respectively to each.