FCPS Planetariums


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.

Return to the Interactive Projector 

Main | About | Ask a Planetarian | Constellations | Interactive Projector | Curriculum | Monthly Celestial Events | Sky Events Calendar | Links

FCPS Home Page
Fairfax County Public School Planetariums
Rebecca Hinze-Pifer, Curator
Last updated December 18, 2008