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[hee-lee-uh-stat] /ˈhi li əˌstæt/
an instrument consisting of a mirror moved by clockwork, for reflecting the sun's rays in a fixed direction.
1740-50; < New Latin heliostata. See helio-, -stat
Related forms
heliostatic, adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for heliostat
  • Exposure is controlled by a fast-moving shutter and by pre-programmed heliostat movement.
  • Each heliostat has mirrors with a slight curvature to focus the sunlight.
  • In order to reflect their images onto the central receiver, the heliostat must track the sun in two axes.
  • The heliostat consists of a large mirror mounted on a two-axis gimbal inside a dome attached to the facility.
  • The heliostat field represents the largest fraction of the cost of a solar central receiver system.
  • Test new tower receiver panel and explore low cost heliostat options.
  • Each heliostat would be configured with two mirrors hung in the portrait position.
British Dictionary definitions for heliostat


an astronomical instrument used to reflect the light of the sun in a constant direction
Derived Forms
heliostatic, adjective
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
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Encyclopedia Article for heliostat

instrument used in solar telescopes to orient and focus sunlight along a fixed direction. A typical heliostat consists of a flat plane mirror and a curved parabolic mirror. The plane mirror is mounted along an axis parallel (i.e., equatorial) to the Earth and rotated slowly by a motor to reflect light from the Sun. The parabolic mirror focuses the reflected rays into the telescope along a fixed direction while the Sun traverses the sky. Therefore, as the telescope's field of view rotates, different celestial objects move quickly into view

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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