Position of the Sun

The position of the Sun or the direction of the Sun in the sky is a function of both the time and the geographic location of observation on Earth's surface. As Earth orbits the Sun over the course of a year, the Sun appears to move with respect to the fixed stars on the celestial sphere, along a circular path called the ecliptic.

Earth's rotation about its axis causes diurnal motion, so that the Sun appears to move across the sky in a Sun path that depends on the observer's latitude. The time when the Sun transits the observer's meridian depends on the longitude.

To find the Sun's position for a given geographic location at a given local time, one may proceed in three steps:

  1. calculate the Sun's position in the ecliptic coordinate system,
  2. convert to the equatorial coordinate system, and
  3. convert to the horizontal coordinate system.

The resulting Sun angles are the solar zenith angle and solar azimuth angle, which can be used to depict the Sun path.

This calculation is useful in astronomy, navigation, surveying, meteorology, climatology, solar energy, and sundial design.

This article is issued from Wikipedia. The text is available under Creative Commons Attribution-Share Alike 4.0 unless otherwise noted. Additional terms may apply for the media files.