A planetarium educational device which illustrates the relative positioning and movement of the earth, moon, sun and other celestial objects in the solar system. The device also provides an illustrative means for depicting the changes in the ocean tides with respect to time, the time changes of selected points on the earth as the earth cycles through a day as well as a means for visually determining the portion of the earth in each day and for measuring of the elevational position of celestial objects above the horizon, azimuths and for generally teaching various aspects of celestial navigation.