Prague Astronomical Clock

The Prague Astronomical Clock is a medieval astronomical clock at Old Town Square in the Czech Republic, mounted on the southern wall of the Old Town Hall. The astronomical dial shows the positions of the Sun, Moon, and zodiac constellations through a complex system of mechanical components, complemented by a calendar dial below.

Clockmaker Mikuláš of Kadaň and astronomer Jan Šindel created this mechanical work in 1410, making it the third-oldest astronomical clock in the world. Over the centuries, the mechanism was expanded and restored several times, particularly after severe damage during World War II.

The mechanism presents an hourly parade of twelve apostle figures, accompanied by a skeleton ringing the bell and representing the cycle of life and death. Tourists gather in the square to watch this brief performance, which has been part of urban life here for centuries.

Visitors can observe the mechanical performance every hour between 8 AM and 11 PM, with the best viewing spots directly in front of the clock. The square fills up quickly just before the hour, so arriving a bit early helps secure a good view.

The clock combines four different time measurements: Babylonian time, Old Czech time, German time, and Sidereal time through separate mechanical systems. Each of these time mechanisms operates simultaneously on the dial, showing how differently people in the Middle Ages calculated the hours of the day.

Location: Old Town

Location: Prague 1

Inception: 1410

Creator: Mikuláš of Kadaň, Jan Šindel

Subject: local mean time, planetary hours, Italian time, sunrise, daytime, sunset, twilight, night, dusk, dawn, equator, Tropic of Cancer, Tropic of Capricorn, zodiac, sidereal time, ecliptic, Sun, Moon, phase of the moon

Part of: Old Town Hall

Website: http://orloj600let.cz

GPS coordinates: 50.08699,14.42070

Latest update: December 26, 2025 23:54