Strasenburgh Planetarium, Rochester Museum & Science Center

Star projector motions, Strasenburgh Planetarium, Rochester Museum & Science Center

Four motions of the star projector: latitude motion shows how the sky changes as you travel north or south over the Earth; diurnal (daily) motion shows rising and setting due to Earth's 24-hour rotation; the rarely used precession motion shows the 26,000-year wobble of Earth's axis. In the second half of the video, the dual Venus projector goes through a cycle, steered by two wheels, one representing the revolution of Earth, the other the revolution of Venus around the Sun. The projectors stay aligned with the line of sight from Earth to Venus and project a Venus dot onto the dome.