TIMEPIECE INDICATING PART OF EARTH OBSERVABLE FROM MOON

摘要

PURPOSE: To provide a clock which can indicate which part of the surface of the earth is visible from the moon by providing an astronomical display means for showing the surface part of the earth which is visible from the moon on a world map, visible at least from a part of a dial. CONSTITUTION: An astronomical display means is installed coaxially with needles 2, 3 below a dial 5 and is formed by a rotary disc 13, provided with a circulating figure 11 of the earth which follows one complete rotation on an axis of the earth. The figure 11 appears continuously, so that the rotation of the dial 5 at a predetermined angle from an opening 9 of the dial 5 is converted into the rotation of the earth corresponding to it, in accordance with the rotation of the disc 13. Since the figure 11 of the earth visible from the opening 9 shows the earth visible from the moon, the disc 13 must in effect complete its rotation in 24 hours 48 minutes 45.78 seconds. Consequently, a person who wears the clock can obtain accurate indication of a part of the earth which is visible from the moon by watching the clock.