The Fascinating History of Prague’s Astronomical Clock


For centuries, Prague’s astronomical clock has kept track of both time and the movements of celestial bodies. Built into the side of the Old Town Hall, the clock is well worth a visit for anyone travelling to Prague. Be sure to plan a trip to the clock once you’ve settled in from your airport shuttle service.

The clock is the oldest working astronomical clock in the world (and the third oldest in recorded history). It was built in 1410, with the other features (sculptures, the procession of figures, the calendar, etc.) added in subsequent centuries. The most recent original addition is that of a golden cockerel, which was added in the mid-nineteenth century.

As it is located in the heart of Prague’s Old Town, which isn’t very accessible to cars, you might want to consider asking your airport shuttle service driver to drop you off somewhere nearby, before enjoying a walk through the picturesque streets until you reach the clock.

Telling the Time

The hand pointing to the Roman numerals around the edge of the clock gives you the current local time in twenty-four hour format. This is the quickest and easiest way to read the clock – it is far more intricate than that, however. The golden arcs covering much of the clock face represent hours as a function of the seasonal day length: one hour is one twelfth of the day’s total daylight, and therefore these divisions describe the length of an hour at different points of the year.

Another interesting method of telling time on the clock comes in the form of the numbering around the outer rim of the face. The hand pointing to these numbers indicates the Old Czech Time. This is measured in hours after sunset, with sunset being at the twenty-fourth hour of every day, and was helpful in the past because anyone able to read the clock could instantly tell how long they had until they ran out of natural light. Historically, church bells would ring for the first twelve hours, after which one would have to look at the clock to know the time.

The hand topped with a small star indicates ‘sidereal’ time against the Roman numerals. Sidereal time is the time used by astronomers in order to track stars night after night, and a sidereal day is usually a few minutes shorter than a solar day. This means the clock is able to tell three different kinds of time.

Astronomical Features

In addition to being able to tell sidereal time as described above, the clock also has other astronomical features. It is able to tell the position of the spring equinox, as well as the position and phase of the moon (i.e. whether it is crescent, gibbous, full, etc.). The clock can also describe astronomical day and night. The smaller circle within the face describes the position of the sun on its perceived path, and is divided according to signs of the zodiac.


There are two sets of moving figures driven by the clock. The earlier set, added in the mid-seventeenth century and made of painted wood, is the four figures with two on either side of the clock. The later set, dating back to the late eighteenth century, is a depiction of the Twelve Apostles. When the clock strikes, the four figures move, with the skeleton (who represents death) ringing a bell to signal the hour, while the others (representing usury, decadence and vanity) shake their heads, and above them the Apostles are displayed in procession.

Reaching the Clock

There are myriad hotels within Prague’s Old Town, so if you’re staying at one of those you may well be within walking distance. If you’re going straight from the airport, shuttle services can take you either to your hotel or, upon request, to the Old Town, where you can walk to the clock. This, however, may only suitable for those who travel light, and the rest may want to use the airport shuttle service to reach their hotel before travelling to the clock by other meansFree Web Content, such as the bus or the metro.

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