PURPOSE: To demonstrate the observation of another planet as seen from the earth.
DESCRIPTION: Turning the crank on the back of the apparatus rotates the two planets around the sun, with the inner planet rotating at about four times the angular speed of the outer planet. The side of each planet opposite the sun is painted black to simulate a shadow. The rod between the two planets aids in fixing the observational line of sight.
REFERENCES: (PIRA 8A10.55) See Demonstration Reference File for information and drawings of this apparatus.
EQUIPMENT: Retrograde Motion Demonstrator.
SETUP TIME: None.
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