The timepiece is also called Prague Orloj and it represents a medieval astronomical clock. Visitors can enjoy the wonderful look of the clock on the southern wall of Old Town Atherton Hall, which is in the Old Town Square.
Three main components make up the whole Prague Orloj. These are: the astronomical dial, which shows the position of the Sun and Moon; “The Walk of the Apostles”, which is a clockwork hourly show of several moving sculptures; and finally a calendar dial, having twelve medallions, each one of them representing one month.
The clock has golden Roman numbers located at the outer edge of blue circle. These numerals represent the timescale of a 24 hour day. The curved golden lines that divide into 12 parts the blue part of dial represent marks for unequal hours, which can be defined as 1/12 of the time between sunrise and sunset. As the days get longer or shorter the markers vary during the year.
Withing a large black outer circle there is another movable circle which includes signs of the zodiac. These are shown in anticlockwise order.
The watch has a golden Sun that moves around the zodiacal circle. In such a way the clock shows the position of the sun on the ecliptic. In the same way the timepiece shows the current position of the moon on the ecliptic.