Astronomical Clock Keeps Time with the Heavens


The new year invariably inspires reflections on the passage of time — in my case, I’ve been pondering the 600-year history of the Prague Astronomical Clock (or Prague Orloj), mounted on the southern wall of Prague’s Old Town Hall in the Czech Republic.

It’s an impressively complicated timepiece. There is an astronomical dial — essentially a mechanical astrolabe — showing the position of the sun and the moon; an hourly “Walk of the Apostles” featuring moving statues of the 12 apostles; and a calendar dial showing the months.

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There are also four carved wooden figures that are set in motion each hour, representing Vanity, Greed, Death, and Blasphemy (the Infidel). And yes, there’s an iPhone/iPad app for that — three, in fact, all based on the Prague Orloj.

Legends abound about this horological masterpiece. For a long time, based on a 1552 report, people thought a clockmaster named Jan Ruze (also known as Hanus) built the clock in 1490, and was subsequently blinded by order of Prague Councillors so he couldn’t build any more of them. Why? Who knows.

But in fact, the earliest parts of the clock (mechanical and astronomical dials) were built in 1410, the joint project of a clockmaker named Mikulas of Kadan and a professor of math and astronomy named Jan Sindel. It’s possible that Hanus may have been responsible for the addition of the calendar dial and clock facade in 1490, however.

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Naturally there have been multiple repairs over the centuries, even a spot of rebuilding here and there, but there are few such marvels from medieval times that have survived to the present day.

Last October, the city of Prague celebrated the clock’s 600th anniversary with an amazing light show: several animated videos were projected onto the clock tower, showing its internal mechanisms as well as various high points from the clock’s (and Prague’s) colorful history. The video is below; see if you can spot the references to the Crusades and the May 1945 Prague Uprising, during which German artillery badly damaged the clock.

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But it’s still standing — a testament to the indomitable human spirit. Ponder that as 2011 gets underway.

The 600 Years from the macula on Vimeo.

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