This Sun Position Calculator will calculate the position of the bottom and top of the Sun's rim, sunset and sunrise time at any geographical location (characterized by observational height, latitude and longitude) at any date (between 1900- 2100) and time. SPC will also indicate the twilight or when the Sun is not visible. A table with latitudes and longitudes, and GMT+ for some major cities around the world is also incorporated.

The Sun's position is characterized by the elevation angle relative to the horizon and azimuth relative to the North direction. Since the observed position of the Sun can be effected by the refraction of the light rays in the atmosphere (especially for low elevation angles), the program gives both the real position of the Sun (without atmospheric refraction) and the observed elevation and azimuth (when atmospheric refraction is accounted). The same remarks are valid for sunset and sunrise time. Atmospheric refraction is taken into account in a more realistic manner, than in other available Sun Position Calculators. We compute the refraction corrections by using a Standard Atmosphere model. In order to approach a realistic atmosphere profile the program needs as input the expected temperature and pressure for an arbitrary chosen altitude.

This is a freeware program, comes with no warranty. It has not yet been sufficiently tested. The program runs under WINDOWS environment (Windows 98 or higher).