The clock uses a stereographic projection of the sky rather than a standard circular map to represent astronomical positions.
The legend of Master Hanuš being blinded to prevent him from replicating the clock is a historical myth; records show he was a clockmaker hired to repair it, not build it.
The calendar dial was added later, in 1490, by the clockmaker Jan Růže.
During World War II, the clock sustained severe damage during the Prague Uprising in May 1945 and required significant reconstruction.
The clock captures Babylonian time, where the length of an hour changes based on the length of daylight throughout the seasons.
The figures on the clock represent vices and virtues, including vanity, greed, and death, which were added during the 17th-century Baroque modifications.
A specialized gear system allows the clock to track the movement of the sun through the zodiac signs.
The clock's internal mechanism features a 'calendar drum' that rotates once per year to update the date.
The Prague Astronomical Clock, or Orloj, is a medieval astronomical clock installed in 1410, making it the third-oldest of its kind in the world and the oldest still in operation. Located on the southern wall of the Old Town Hall, the machine consists of three primary components: the astronomical dial representing the position of the sun and moon, a calendar dial with medallions representing the months, and the 'Walk of the Apostles' mechanical figure display. The astronomical dial features a stereographic projection of the local Prague sky, tracking the sun and moon's positions against a background of fixed stars. Its mechanical movement has undergone multiple restorations since the 15th century to maintain its functional precision. The clock face displays several types of time simultaneously, including Central European, Old Bohemian, and Babylonian time. The current mechanism houses a complex gear system that controls the movement of the zodiac ring and the planetary spheres. The clock's intricate automata perform a sequence of movements during the display, which serves as a landmark event in the city's tourism. It is integrated into the structural facade of the Gothic Old Town Hall tower.
From the center of the Old Town Square looking toward the Old Town Hall to capture the full architectural frame of the clock.
Arrive at least 15 minutes before the hourly mechanical performance to secure a view of the upper clock face.
Observe the clock from the perspective of the Old Town Square to watch the crowds and the movement simultaneously.
Visit the clock tower interior separately for a view of the machinery and a panoramic outlook over the city.
Do not stand directly under the clock face during the show if you dislike heavy crowds, as pickpockets often target the dense mass of tourists.
The clock operates year-round; however, the tower and interior exhibition may be closed on specific public holidays or for periodic maintenance.
