Prague’s Astronomical Clock

Prague’s Astronomical Clock

Take a journey to the center of the Old Town Square in Prague and look up…Chances are you’ll immediately notice the Orloj, Prague’s astronomical clock, on the southern wall of the Old Town Hall.

First installed in 1410, this clock is the third oldest astronomical clock in the world, and the oldest one still in operation. The clock is beautiful, full of history, and begging for a visit during your next trip to the Czech Republic. The face of the clock is stunning and complex. It features an astronomical dial, three hands, a solar plate, a rotating Zodiacal ring, an outer rotating ring, and several figures. A calendar plate hangs below the main face of the clock. This particular plate is a replacement from 1880; the original calendar plate is preserved in the Prague City Museum.

The Orloj is a beautiful and intricate machine. Let’s take a look at the key elements of Prague’s astronomical clock:

Astronomical Dial
The astronomical dial signifies the time of day and position of the moon and the sun in the sky. The dark blue circle in the center represents Earth, the upper blue portion represents the sky above the horizon, and the orange and black represent the sky below the horizon. The sun icon sits in the blue horizon area during daylight hours and sinks into the orange and black areas in the evening hours. The left side of the clock aligns with the dawn; the right side with dusk.

Standard Roman numerals adorn the clock face and indicate local time in Prague on a standard 24-hour model.

The outer ring of the clock is made up of golden Schwabacher numerals, which indicate Old Czech time. This ring rotates through-out the year to indicate the time of the sunset, denoted by the 24th numeral.

Zodiacal Ring

The inner ring is the Zodiacal ring and showcases the 12 signs of the standard zodiac. The ring indicates which sign the sun is currently residing in on the zodiac calendar. The signs are listed anticlockwise. The sun medallion moves through this ring. You can tell the time in this ring, with the help of the sun, in three ways:

  • The positioning of the hand over the Roman numerals indicates local Prague time.
  • The sun’s placement over the curved golden lines denotes uneven hours.
  • The position of the hand over the outermost ring represents the number of hours passed since sunset in Old Czech Time.

The moon medallion, half silver and half black in color, also moves through this ring and indicates the lunar phases. The moon medallion moves more quickly than the sun, as it mimics the moon’s orbit of the Earth and is powered by gravity.

The clock’s interior is a complex system of gears. A 365 tooth gear operates the sun medallion, a 379 tooth gear works the moon medallion, a 57 tooth gear rotates of the moon medallion on its arm, a 366 tooth gear moves the zodiac ring, and a 24 tooth gear connects the sun and the moon medallions.

“The Walk of the Apostles”
Four figures adorn the outside of the clock and move upon the changing of the hour. These figures symbolize vices. On the left of the clock face Vanity holds a looking glass, and next to him Greed holds bags of money. To the right of the clock face, a skeleton represents Death, next to him a Turk, representing Vice and Lust, plays the lute. Every hour, the skeleton will ring the bell, and the three other figures will shake their heads no, signifying that they are not yet ready to die.

In two windows above the main clock, Jesus and the Apostles parade every hour on the hour. This feature was added in the 19th century.

The astronomical clock is rich in legend. According to the most famous legend, after the clock was built by Master Hanuš in 1410, the Prague city councilors were so impressed that they feared he would build a second one in another city. One night the councilors had Master Hanuš blinded, thus ensuring Prague would have the only astronomical clock. Hanuš, broken, finished the clock and then ended his life by way of the clock’s clogs. It’s said that no one will ever be able to repair or work on the clock for fear of Hanuš’ ghost.

Whether or not this legend is true, what is certain is that for 600 years the clock has been one of the greatest treasures of the city. Its unique face and the hourly procession of Apostles makes Prague’s Orloj like no other instrument in the world.

Intrigued? See this amazing time-piece and many other highlights on one of our guided vacations to the Central & Eastern Europe!

Arianna Ambrutis

Having spent much of her life as nomadically as possible, Ari found a home with GET. As far as her travels have taken her, she's worked on an archaeological dig in Israel, sailed around Greek isles, experienced a crazy sunburn in Turkey, adores tomatoes in Italy, and thinks Paris and New York are just the bee’s knees. With her degree in Cultural Anthropology, Ari loves exploring a culture’s traditions, colloquialisms, and (most importantly) cuisines.

2 thoughts on “Prague’s Astronomical Clock

  • June 11, 2019 at 12:20 pm

    I’m interested in visiting the Czech Republic, ideally for 14 days next Sep. or October. Flying from
    Florida to Europe. Staying at a local hotel with planned tours around the country. Please let me know if your company provide that type of service arrangement. Thanks.

    • June 13, 2019 at 8:07 am

      Hi Maria –
      Please reach out to one of our many Travel Specialist at 1-877-622-9109. Any of them will be able to find you the perfect trip according to your preferences.
      Happy travels!


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