A heliostat on top of the Swedish Solar Telescope. The Swedish Solar Telescope (or SST is a 1 m telescope at Roque de los Muchachos Observatory, La Palma in the Canary Islands.

A Heliostat (from helios, the Greek word for sun, and stat, as in stationary) is a device that tracks the movement of the sun. In Greek mythology the Sun was personified as Helios (ˈhiliˌɑs ( Ἥλιος Latinized as Helius) The Sun (Sol is the Star at the center of the Solar System. It is typically used to orient a mirror, throughout the day, to redirect sunlight along a fixed axis towards a stationary target or receiver. A mirror is an object with a surface that has good Specular reflection; that is it is smooth enough to form an Image.

Heliostats are used in solar telescopes, and solar power generation. A solar telescope is a special purpose Optical telescope used to observe the Sun. Solar energy is the Light and radiant heat from the Sun that powers Earth 's Climate and Weather and sustains Life Heliostats have been used in surveying in the form of a heliotrope to constantly reflect sunlight in a single fixed direction, allowing the accurate observation of a known point from a distance. Surveying is the technique and science of accurately determining the terrestrial or three-dimensional space Position of points and the distances and angles between The heliotrope is an instrument that uses a Mirror to reflect Sunlight over great distances to mark the positions of participants in a land survey.

The simplest heliostat devices use an equatorial mount and a clockwork mechanism to turn the mirror in synchronisation with the rotation of the Earth. An equatorial mount is a mount that has one rotational axis parallel to the Earth's axis of rotation More advanced heliostats track the sun directly by sensing its position throughout the day. Others are controlled by computers.

A siderostat is a similar device which is designed to track a fainter star, rather than the Sun. A star is a massive luminous ball of plasma. The nearest star to Earth is the Sun, which is the source of most of the Energy on Earth

Large scale projects

A photo of one of Solar Two's heliostats taken in 2003. The solar power tower can be seen in the background. The solar power tower (also known as 'Central Tower' power plants or ' Heliostat ' power plants or power towers is a type of Solar furnace using a tower to receive

Many heliostats can be combined together to concentrate the sun's energy. Energy can be collected for electrical generation with photovoltaic cells or can be used to heat a medium such as water or molten salt, as in the The Solar Project. Photovoltaics ( PV) is the field of technology and research related to the application of Solar cells for Energy by converting Sunlight directly The Solar Projects Solar One, Solar Two and Solar Tres are power plants based on Solar thermal energy in the Mojave Desert and Spain The high temperatures can also be used as an incinerator for waste disposal.

See also

• Renewable energy
• Solar cell
• Solar power
• Solar power tower
• Solar thermal energy
• Solar tracker

External links

• Field of 63 heliostats at the Odeillo Solar Furnace
• Solar Furnaces at Odeillo
• redrok.com