A heliostat (from helios, the Greek word for sun, and stat, as in stationary) is a device that includes a mirror, usually a plane mirror, which turns so as to keep reflecting sunlight toward a predetermined target, compensating for the sun's apparent motions in the sky. Nowadays, 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. A few are used experimentally to reflect motionless beams of sunlight into solar telescopes. Before the availability of lasers and other electric lights, heliostats were widely used to produce intense, stationary beams of light for scientific and other purposes.Black metal and brass object with scale measure (0 - 90 and glass circle on top that can be raised and lowered. Three legs with brass feet.Markings on scale measure. heliostat, metal, brass, mirror, guage

Information sheet next to object details history, purpose and use. A pillar was constructed for the instrument in 1863.Heliostat consisting of brass cylindrical body on metal stand.Engraved on face: “J.C. Silbermann Invleur Tuit por J.Dubosq i Paris” “No. 119”

Heliostat Light source used in Brownian Motion Film, made in 1934 by L.W. and E.J.H