A solar tracker is a device that orients a payload toward the Sun. Payloads are usually solar panels, parabolic troughs, Fresnel reflectors, lenses, or the mirrors of a heliostat. For flat-panel photovoltaic systems, trackers are used to minimize the angle of incidence between the incoming sunlight and a photovoltaic panel, sometimes known as the cosine error. Reducing this angle increases the amou. Basic conceptSunlight has two components: the "direct beam" that carries about 90% of the solar energy and the "diffuse sunlight" that carries the remainder – the diffuse portion is the blue sky on a clear day, and is a larger prop. Solar collectors may be non-concentrating flat-panels, usually photovoltaic or hot-water, or concentrating systems, of a variety of types. Solar collector mounting systems may be fixed (manu.