What Is an Astronomical Clock and How Does It Work?

More than 600 years ago, on October 9th, 1410, a special clock started ticking in Prague, the capital of the Czech Republic. This astronomical clock is set on the western wall of the city’s old city hall building. One of the most popular tourist attractions in Prague, the clock was built in the middle ages but it still fully operates to this very day. Not only that, but most of its parts, including the main mechanical center, are the original ones from all those centuries ago!
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The original mechanical center of the clock was installed by clockmaker Mikuláš of Kadaň and astronomy professor Jan Šindel. In 1940, clock artist Jan Růže (sometimes known as Hanuš) added the calendar and the figurines around it. In 1886, the clock underwent some renovations, and today it is also operated with the help of an uber-accurate mechanism called a chronometer. In the middle of the 19th century, painter Josef Mánes decorated the clock with scenery paintings of the four seasons. The clock differed great damage during WWII when the building it’s mounted on burned. Thankfully, it was quickly repaired.

All the time in the world

The clock is not only special because of its history. Apart from telling what time of the day it is, reading it can also tell you what day of the month and year it is! The clock’s elaborate mechanism also measures three different types of time: central Europe time, old Czech Republic time, and Babylonian time. The latter might sound like something we made up, but it’s totally real. Babylonian time (AKA Planetary hours) is no longer in use but the ancient Babylonians developed it based on planetary movement to tell time. All those different time measures are possible thanks to the astronomical dial in the center of the clock. This dial is made of an ancient navigation tool called an astrolabe, which id pointed at the north pole.

Last of its kind

The clock can also tell you the locations of different astronomical bodies and which astrological sign is at the top of the zodiac at the moment. It is the last and only astronomical clock in the world to provide all this incredible information.