Is the Prague Astronomical Clock Accurate?

By Robert Palmer

The Prague Astronomical Clock, also known as the Prague Orloj, is a medieval astronomical clock located in the Old Town Square of Prague, Czech Republic. The clock was first installed in 1410 and has since become one of the most popular tourist attractions in Prague. However, many people wonder if the clock is accurate or not.

History of the Prague Astronomical Clock

The Prague Astronomical Clock was designed and built by a master clockmaker named Mikulas of Kadan in collaboration with Jan Ondrejuv, a professor of mathematics and astronomy at Charles University in Prague. The clock was then later improved by another famous clockmaker Hanus.

The clock is made up of three main components: the astronomical dial, the calendar dial, and the hourly show of figures.

The Astronomical Dial

The astronomical dial is the oldest part of the clock and displays various astronomical details such as the position of the sun and moon in relation to Earth’s horizon. It also displays sidereal time and has a zodiac circle showing each sign.

The Calendar Dial

The calendar dial shows various details about both Christian holidays and Czech festivals. It displays information about which saint’s day it is, as well as which animal represents each month.

The Hourly Show of Figures

Lastly, every hour on the hour, there is a show that takes place on the clock face where 12 apostles appear from two windows above the astronomical dial.

Is The Prague Astronomical Clock Accurate?

Many people have questioned whether or not this ancient timepiece is accurate. On one hand, it was built using medieval technology so one might assume that it cannot be accurate compared to modern-day clocks. However, this assumption may be incorrect.

While there have been some inaccuracies throughout its history, the clock has undergone several restorations and renovations that have updated the clock’s mechanisms. The last major renovation took place from 2018 to 2019, in which the clock was completely disassembled and cleaned. During this renovation, experts also made sure that all of the mechanisms were working properly.

However, there are some notable inaccuracies in the clock’s design. For example, while the astronomical dial displays sidereal time accurately, it does not display mean solar time (which is what modern clocks display) as accurately. Additionally, because of its age and complexity, it is difficult to maintain and keep accurate over long periods of time.

Conclusion

In conclusion, while the Prague Astronomical Clock may not be as accurate as modern-day clocks due to its age and complexity, it is still a marvel of medieval engineering that has stood the test of time. It is a fascinating piece of history that continues to captivate tourists from all over the world with its intricate design and hourly show of figures.