Piece watch indicating the part of the visible Earth from the moon.

摘要

The watch includes a conventional analogue display with an hour hand (22) and a minute hand (23) moving over the face (25), and a correcting knob (27) on the side. The face carries a view of the terrestrial globe in polar projection, centred on the axis of the hands. A further indicator comprises a T-shaped, with the cross bar of the T extending along the full diameter of the watch face, and the shorter stem (27b) ending in a crescent shape (27b). This bar turns with a period of 24 hours, 28 minutes 45.78 seconds, being the period of rotation of the earth as seen from the moon.