Retrograde Motion of Mars - Heliocentric and Geocentric View的副本
Left Side is a Heliocentric View of the Sun ( Yellow), Earth ( Blue ) and Mars (Red)
Buttons are provided to start and stop time - a time slider is also available
Right Side shows the same objects seen from a Geocentric view
The Right Ascensions of the Sun and Mars are shown as well as the Prograde/Retrograde nature of the motion of Mars