The Position of the Sun
This report describes research done at the Artificial Intelligence Laboratory of the Massachusetts Institute of Technology. Support for the laboratory's artificial intelligence research is provided in part by the Advanced Research Projects Agency of the Department of Defense under Office of Naval Research Contract N00014-75-C-0643.
The appearance of a surface depends dramatically on how it is illuminated. In order to interpret properly satellite and aerial imagery, it is necessary to know the position of the sun in the sky. This is particularly important if this interpretation is to be done in an automated fashion. Techniques using relatively straightforward methods are presented here for calculating the position of the sun with more than enough accuracy. Caution: Do not use this technique for navigational purposes. Correction terms have been omitted; as a result, the ephemeris data calculated may be in error by about one minute of arc, an amount which is of no significance for the application of this data in image analysis.