Heliostat
device that includes a mirror, which turns so as to keep reflecting sunlight toward a predetermined target
A heliostat (from Ancient Greek ἥλιος (hḗlios) 'sun' and στατός (statós) 'standing') is a device that reflects sunlight toward a target, turning to compensate for the Sun's apparent motion.
The reflector is usually a plane mirror.
The target may be a physical object, distant from the heliostat, or a direction in space. To do this, the reflective surface of the mirror is kept perpendicular to the bisector of the angle between the directions of the Sun and the target as seen from the mirror. In almost every case, the target is stationary relative to the heliostat, so the light is reflected in a fixed direction. According to contemporary sources the heliostata, as it was called at first, was invented by Willem 's Gravesande (1688–1742). Other contenders are Giovanni Alfonso Borelli (1608–1679) and Daniel Gabriel Fahrenheit (1686–1736). A heliostat designed by George Johnstone Storey is in the Science Museum Group collection.
Currently, most heliostats are used for daylighting or for the production of concentrated solar power, usually to generate electricity. They are also sometimes used in solar cooking.
The public source identifies “Heliostat” as device that includes a mirror, which turns so as to keep reflecting sunlight toward a predetermined target. This brief keeps that definition visible, then builds a research path around Heliostat, device and includes.
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This entry incorporates text from “Heliostat” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.