Fairfax County Public Schools Planetarium Website with Spitz Projector


The Planet Analogs

planet analogs

The planet analogs are gear systems which project the five visible planets in the planetarium sky. There is a motor inside the projector housing which turns a gear in each of the analogs. The gear turns another gear which rotates a metal rod with a mirror on its end. A light shines into the mirror and is reflected onto the dome, marking the position of one of the five visible planets.

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Fairfax County Public School Planetariums
Rebecca Hinze-Pifer, Curator
Last updated September 27, 2008