A heliostat (from helios, the Greek word for sun, and stat, as in stationary) is a device that, in general, tracks the movement of the sun. The device typically utilizes a mirror, which can be oriented throughout the day to redirect sunlight along a fixed axis toward a stationary target or receiver. Heliostats are used in solar telescopes, and solar power generation. Heliostats have been used in surveying in the form of a heliotrope to constantly reflect sunlight in a single fixed direction, a… (More on Heliostat)