Locating the sun

In many solar energy applications, there is a need for an accurate method of locating the sun. A means for calculating the sun's position as a function of time is presented. The fundamental reference frames for observing celestial objects are defined, and the basic notions of orbits and time reckoning are explained. A brief description of a computer program to track the sun is given. The effects of errors in locating the sun on insolation predictions are examined.