The moon, a globe of 1.2 m. in diameter, is located above the planetarium between the two windows. The globe is subdivided in two hemispheres, one gilded and the other one black. In this way the globe alternatively shows the two faces in perfect synchronization with the movements and the relative phases of the moon which rotates on its own azis and performs a full revolution in 29 days, 12 hours, 44 minutes and 3 seconds.