THE ASTRONOMICAL CLOCK IN PRAGUE


Astronomical dial
Current Setting of Astronomical Dial

THE 605 YEARS OF PRAGUE ASTRONOMICAL CLOCK

On the south side of the tower of the Old Town City Hall is one of the most attractive sights of Prague. It was made at the latest in 1410. The Prague astronomical clock (orloj) is equipped with two large dials. The upper dial is astronomical; the lower is a calendar dial. At first sight it might not be obvious what exactly this basic, precisely designed part of the clock shows, or even that it works at all. That's not really surprising, because the clock - both its astronomical and calendar part – is evidence of the knowledge and skill of our ancestors, a skill developed from one generation to the next. Thanks to them and historical good fortune, the Prague astronomical clock has been preserved, and even today we can admire this ingenious model of the universe, which is driven by a clock mechanism.


Dr. Petr Hadrava with Participants of General Assembly of International Astronomical Union in front of Astronomical Clock (August, 19, 2006)

600th ANNIVERSARY OF PRAGUE ASTRONOMICAL CLOCK

Until the seventeenth century the astronomical clock was, for the inhabitants of Prague, the main source of time and publicly available calendar data, as well as information about the position of the Sun, Moon, and signs of the zodiac. The Prague astronomical clock can boast an absolutely unique feature, a feature that the observer from outside doesn't immediately notice - namely, part of the precisely operating mechanism is original. Above all, I mean the mechanism that moves the pointers of the zodiac, Sun, and Moon. It consists mainly of three, large, forged cogwheels, all of which turn independently but on a single shaft. The first wheel, with 365 cogs (or teeth) turns the zodiac hand. The second wheel, with 366 cogs, turns the Sun hand. And the third wheel, with 379 cogs, turns the Moon hand.


(14 laminated full color pages 12x27 cm)

You can buy in Prague Old Town City Hall or in Kepler Museum (Karlova 4) or by e-mail: provas@volny.cz

Price: 4,- Euro/pc - Available in Czech, English, French, German, Italian, Japanese, Hungarian and Spanish