a telescopic device for reflecting the light of a star in a constant direction, the chief component of which is a plane mirror turned by a clock mechanism to correct for the rotation of the earth.

Origin of siderostat

First recorded in 1875–80; sidero-2 + -stat
Related formssid·er·o·stat·ic, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for siderostat

Historical Examples of siderostat

  • The telescope was housed at the Exhibition in a long gallery pointing due north and south, the siderostat at the north end.

  • The siderostat, twenty-seven feet high, and as many in length, weighed forty-five tons.

  • The movable portion of the roof of the building had been slid back, and the mirror of the siderostat stood bared to the sky.

British Dictionary definitions for siderostat



an astronomical instrument consisting essentially of a plane mirror driven about two axes so that light from a celestial body, esp the sun, is reflected along a constant direction for a long period of timeSee also heliostat Compare coelostat
Derived Formssiderostatic, adjective

Word Origin for siderostat

C19: from sidero-, from Latin sidus a star + -stat, on the model of heliostat
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