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Astronomical Tower of the Clementinum

The Astronomical Tower, formerly also called the Mathematical Tower, is the dominant feature of the Clementinum in the Old Town of Prague.[1] From 1751 it was used for astronomical observations, until 1938.[2]*

History

The Jesuits built the tower in 1722, but it has not survived in its original form. The rebuilding lasted roughly from 1749 to 1777, and the structure reached its top in 1751.[1] The Heritage Catalogue of the National Heritage Institute names František Maxmilián Kaňka as the author of the observatory tower.[3] During the rebuilding the Jesuit order was dissolved by a papal bull on 21 July 1773.[1] The mathematician, physicist and astronomer Josef Stepling (1716–1778) was responsible for equipping the tower with astronomical instruments.[1]

Weather records and true noon

Meteorological measurements at the tower date back to 1752 and have been made regularly and systematically since 1775.[2][1] On the second floor is the Meridian Hall, which served as a camera obscura for determining true noon with a stretched string. Its walls hold two original mural quadrants for measuring star positions.[2] From 1842 to 1928 true noon was signalled to the people of Prague from the tower.[2] A man on the tower determined noon with a sundial and timekeeping instruments and waved a flag. From 1891 to 1911 gunners on the Marian ramparts fired a shot at this signal.[1]

Statue of Atlas

At the top of the tower stands a statue of Atlas carrying a globe with the symbol of the Eye of God. The statue was moved from the original tower and comes from the workshop of Matthias Bernhard Braun.[1]

Today

The tower is part of the Clementinum guided tour run by Prague City Tourism. The tour includes an exhibition of historical measuring instruments, the Meridian Hall, a view into the Baroque library hall and a climb to the tower gallery.[2]

Sources

  1. Magistrát hl. m. Prahy (Praha virtuální)
  2. Prague City Tourism (prague.eu)
  3. Národní památkový ústav (Památkový katalog)

* The sources are collected and the preliminary text of this entry is drafted with artificial intelligence, on the instruction of the editorial staff; the entry has not yet been verified by an editor — report a mistake.