Perpetual calendar including lunar cycle display - has central axis representing position of sun, and rotating discs showing earth and moon

摘要

The perpetual calendar indicates not only the month, the date and the day of the week, but also the seasons, the signs of the zodiac and the position of the moon relative to the earth and the sun. The calendar has a central axis (9), which represents the position of the sun and a support disc (8) marked with the dates, the months of the year and the days of the week. An element (11) representing the earth rotates about the central axis (9), to indicate the earth's position and itself carries a rotatable index (14) to represent the position of the moon.