Oldest astronomical clock in Prague has been functioning since 1410.
The Prague astronomical clock, or Prague orloj is a
medieval astronomical clock located in Prague, the
capital of the Czech Republic. The clock was first
installed in 1410, making it the third-oldest
astronomical clock in the world and the oldest one still
working. The clock mechanism itself is composed of
three main components:
1. the astronomical dial, representing the position of the Sun and
Moon in the sky and displaying various astronomical details.
2. “The Walk of the Apostles”, it hourly show of figures
of the Apostles and other moving sculptures.
3. calendar dial representing the months.
The astronomical dial has a background that
represents the standing sky and earth.
it show four main moving components:
the zodiacal ring, an outer rotating ring, an icon ring
representing the Sun, and an icon ring representing the Moon.
Inside the black outer circle lies another
movable circle marked with the signs of the zodiac
which indicates the location of the Sun on the
ecliptic. The signs are shown in anticlockwise order.