Astronomical Clock: How To Read It?

The oldest functioning Astronomical Clock in the world dating back all the way to the year 1410. Prague Astronomical Clock was installed in the last decade of the Bohemian Golden Age under the reign of Charles IV. The Astronomical clock show runs every hour sharp from 9 AM till 11 PM.


How to read the Prague Astronomical clock?

Prague Astronomical Clock shows four different times known as Old Czech time, planetary hours, sidereal time, and "German" hours. Which one shows the current hours? The latter illustrates the current time since the mid-16th century. "German" hours are marked with 24 golden Roman numerals along the circle of the astrolabe. You can also find old numerals on the outer frame of the clock dial that indicate Old Czech Time counted from the dawn. It was brought from Italy by the Holy Roman Emperor and Bohemian King Charles IV.

See the explanation of how to read the Astronomical clock in our youtube video!

The unique mechanism of the Prague Clock not only shows us what time and day it is, but also tracks the movement of celestial bodies, or planetary hours, like the Sun and Moon. Depending on their position, predictions of upcoming events were made. People would even decide when to receive popular medical treatments such as bloodletting based on that!

The last time system was added in 1865 for astronomical purposes. Sidereal time rotation lasts 23 hours and 56 minutes.


Fun Facts about Prague Astronomical Clock

  • Prague's Astronomical Clock is the oldest still-functioning clock of this type in Europe, which is working on more than 2/3 of its original mechanism.
  • It is widely accepted nowadays that the famous Prague Clock was constructed by a royal clockmaker Mikulas of Kadan, as opposed to the popular belief that the creator of the mechanism was Master Hanus. This assumption is a product of a legend developed by the writer Bohuslav Balbin, who wrote that Master Hanus was blinded so he couldn't recreate the Astronomical Clock anywhere else.
  • The mechanism of the Astronomical Clock is not accessible to the public, which only perpetuates the rumors about the clock's curse.
  • Another popular legend says, that Master Hanus cursed the Astronomical clock before he died, so anyone who touches it is doomed for a terrible end. 
  • Despite the curse, an expensive reconstruction of the clock, that cost Prague more than 9 million Czech crowns, was conducted in 2018. During that time the Astronomical Clock was closed.  

Prague Astronomical clock figures

There are also four figurines on the side of the clock dial or astrolabe. They symbolize the allegories of Death, Greed, Lust, and Vanity. The figurines move their heads and hands when the clock rings to signalize every hour from 9 am to 11 pm. They are joined by 12 Apostles and a Golden Rooster whose crow ends the procession and the movement of the allegories. Don't miss the show!


Our Local Guide Tip

  • Wake up early to see the first Astronomical Clock show of the day at 9 AM and be one of its only spectators!
  • Make sure to be at the Astronomical Clock 10 min before the show starts, so you can get the best view. The show is rather short and a lot of people come to see it.
  • You can visit the Tower of the Astronomical Clock inside when you get a ticket to the Old Town Hall. It includes the elevator ride to the top of the Clock Tower and a guided tour of Old Town Hall's interiors and underground. For more information, please check out Prague Old Town Hall's official website.

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Author: Valeriia Zahradnikova and Vaclav Zahradnik, Prague guides certified by Prague City Tourism agency. Valeriia and Vaclav have worked in tourism for over 6 years and have guided thousands of Prague visitors.

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