Astronomical Tower in Clementinum

The Astronomical Tower (Astronomicka vez) in Prague is one of the characteristics of Clementinum. To get to the top of this 52-meter-high tower you have to climb 172 stairs of the steep and winding staircase. At the cupola of the Astronomical Tower is a large lead statue of Atlant holding a globe. The tower was built thanks to the university rector Frantisek Retz in 1722.

First it was used only as a view tower, since the mid-18th century the tower was equipped by astronomical devices designed by drawings of professor of mechanics Jan Klein. Jesuits scholars and their students used the tower for astronomical and climate observations. One of the students, Antonin Strnad, started various meteorological and climate measurements in 1775. Since then the measurements are taken regularly, which makes it the longest uninterrupted observation of the climate in the world.

Jesuit astronomers were able to determine the Prague meridian. From 1842 to the 1920’s they informed Prague people about high noon by waving a flag from the tower. The Astronomical Tower served for astronomical observations until the 30’s, then astronomers moved to the new observatory in Ondrejov.

The tower was reconstructed several years ago and opened to the public. Besides the original astronomical devices, visitors can admire the splendid view of the city of Prague.

Klementinum 190, Prague 1

How to get there:
The entrance to the Astronomical Tower is near the Mirror Chapel. To Clementinum you can get e.g. from the Knights of the Cross Square near Charles Bridge.

Opening hours:

January – March 10:00 – 16:00 (every full hour)
April – October 10:00 – 20:00 (every half an hour)
November – December 10:00 – 18:00

Tours are available only with a guide (also in foreign languages). Maximum number of people in one group is 25.

Entrance fee (together with Baroque Library Hall and the Mirror Chapel):

Adults 190 CZK
Students, children over 6 years old 120 CZK
Children below 6 years old free

Tel: 222 220 879

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