Set chart mode to star atlas, the status line to on, and the field to 45°. Set the date to April 1, 2003. Center on Mars and lock the display to Mars. Set the animation trails to on and turn off all the trail labels. Set the time step to 2 days and start the animation. When Mars undergoes a retrograde loop, record the month during which retrograde motion occurs and the constellation in which it occurs. Sketch the shape of the retrograde loop. Repeat these steps for the next three retrograde loops. Use your data to estimate the synodic period of Mars. When do you think the retrograde motion of Mars will appear in the constellation of Aquarius again? Do you see a pattern to the changes from one retrograde loop to the next?
