[ see-luh-stat ]

  1. an apparatus consisting of a mirror driven by clockwork, used to enable a fixed telescope to keep the same area of sky in its field of view by compensating for the apparent rotation of the celestial sphere.

Origin of coelostat

1895–1900; coelo- (for Latin caeli-, combining form of caelum sky) + -stat

Words Nearby coelostat Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use coelostat in a sentence

  • It will be laid comfortably flat on the ground, and the rays of light reflected into it by a coelostat.

    Astronomical Discovery | Herbert Hall Turner

British Dictionary definitions for coelostat


/ (ˈsiːləˌstæt) /

  1. an astronomical instrument consisting of a plane mirror mounted parallel to the earth's axis and rotated about this axis once every two days so that light from a celestial body, esp the sun, is reflected onto a second mirror, which reflects the beam into a telescope: Compare siderostat

Origin of coelostat

C19 coelo-, from Latin caelum heaven, sky + -stat

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012