Simulates the Eudoxus principle. Spheres of Eudoxus model simulates the system devised by the Ancient Greek astronomer Eudoxus to model the motion of the planets. The model consists of four nested concentric spheres. The axis of each sphere is attached to the surface of the next sphere out. The planet itself is located on the surface of the innermost sphere. The outermost sphere rotates with the daily (apparent) rotation of the stars.

Controls
1. Play/Pause: start and stop the simulation.
2. Step: advance by one time step.
3. Reset: reset simulation to original state.
4. Clear Traces: clears all traces from both windows.
5. Tilt: tilt of inner (red) sphere relative to middle (blue) sphere in degrees. Some tilt is required for retrograde motion.
6. Angular Velocity (Blue): sets angular velocity of middle (blue) sphere in units such that the angular velocity of the inner (red) sphere is +1.0. The angular velocity of the blue sphere must be set to -1.0 in order to keep the planet near the ecliptic.
7. Angular Velocity (Green): angular velocity of the outer (green) sphere controls motion of the planet along the ecliptic. If this is set too fast retrograde motion will be impossible.

Requirements:
* Java

The license of this software is Free, you can free download and free use this calculator software.