Project Description

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Project: Long-term planetary motion

Tier: 2

Location: ahcl

Other information, requirements, or equipment you must supply (may be blank): Starry Night or other planetarium software required

Select a planet to observe and run the software to show the planet go through retrograde (note some software programs have built in demos that include retrograde motion).

Observe and describe retrograde motion as seen from Ann Arbor, including the dates when the planet enters and leaves retrograde and how long it takes to go through retrograde.
Determine the sidereal period and apply Kepler's 3rd Law to estimate distances. Sketch the orbit of the planet and the Earth, showing their relative positions at the start, middle and end of the planet's retrograde. Determine the distance between Earth and the planet for each of those positions and label those distances on the sketch.

Correlate your observations with your sketch, and use the sketch to explain the cause of the observations (i.e. if the planet is brightest on feb 2 use the sketch to explain why it is brightest on that day)