The Sun's path above the Horizon
Udo Backhaus, Universitt Duisburg-Essen, Germany

This programs simulates the daily path of the sun above the horizon, its variation during the year
and its dependence from the geographical position of the observer. Furthermore, the program visualizes
the generation of the trace the shadow of a gnomon is running during daylight. In this way, it may
help to understand the method of measuring the sun's position above the horizon and the derivation
of the earth's radius by comparing the results of distant observers.
The program also visualizes the formation of the sun's analemma by daily observations at the same time of day.

The program offers the possibilty of choosing the following parameters:
   - the geographical position of the observer,
   - the date of observation,
   - the time difference between local time and Universal time,
   - the time interval between subsequent positions of the sun and
   - the rotation angle (to change the direction of view).
Additionally, you can choose between the visualisation as a "film" or as a "stroboscopic picture".

In the case of a time step of 24 h the drawing of the analemma may be switched on and off.

