coelostat

[ see-luh-stat ]

noun

, Astronomy.

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.

coelostat

/ ˈsiːləˌstæt /

noun

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

Word History and Origins

Origin of coelostat¹

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

Word History and Origins

Origin of coelostat¹

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

Example Sentences

The corona was photographed by Professor Barnard, at Wadesborough, North Carolina, with a 61-1/2-foot horizontal "coelostat."

From Project Gutenberg