Astronomical clock

from Wikipedia, the free encyclopedia

An astronomical clock is a mechanical clock which, in addition to the time, also shows astronomical facts such as the position of the sun and moon above the horizon and in the zodiac , the phases of the moon and, in rare cases, the positions of the large planets in the sky. Astronomical clocks were initially placed inside churches in the late Middle Ages . Some of their mostly artisan designers were also active as inventors and instrument makers . From the Renaissance onwards, monumental clocks were attached to town halls, city gates or towers. Large room clocks were mostly not made until the Baroque era . They have also been used as table or wrist watches since the 20th century.

Prague Astronomical Clock , an astrolabe clock

The astronomical clocks, like modern clocks with their complications, have, in addition to the hour hand, additional hands and sometimes additional dials . A very clear variant are the older astrolabe clocks , in which, among other things, the rete (star disk) of an astrolabe is evenly rotated with the help of the clockwork .

Emergence

The predecessor of all astronomical clocks was the lost astrarium built by Giovanni de Dondi , which used several dials. One of the first astrolabe clocks was in Strasbourg Cathedral , but it has already been replaced by a second new building without an astrolabe. A few astrolabe clocks are still almost in their original condition and some of them are still running, such as the Prague City Hall Clock and the Bernese Zytglogge Clock . The large number of later clocks without astrolabe, preferably attached to town halls, have largely been preserved and in operation in their original condition. The magnificent room clocks from the Baroque era are mostly in natural science collections and museums. They are also without an astrolabe and sometimes have several dials (multi- dial clocks ) . The zodiac taken over from the astrolabe became a fixed dial scale here. Clocks with such a scaled dial are also called zodiac clocks .

Variants overview

Astronomical clocks can come from different centuries, be different sizes, and serve different purposes. They therefore differ in their appearance and in what and how they display it. The following picture list gives an approximate overview.

  • Dondi Astronomical Clock ,
    1344: Astrarium

  • Astrolabic church clock in Stralsund ,
    1394: Astrolabe clock with original gear train, not in use

  • Astrolabe tower clock in Bern ,
    1405/1530: astrolabe clock

  • Astrolabic church clock in Münster , 1540/42, northern projection (time display counterclockwise)

  • Town hall clock in Esslingen , 1589,
    from below: simple clock, zodiac clock and moon clock

  • Astronomical clock in the Marien-Kirche Rostock ,
    1641/43: zodiac clock with moon phase display

  • Astronomical clock in Besançon , 1858/60, multi-dial clock

  • Modern astrolabic wrist watch, astrolabe watch
    ( Ulysse Nardin )

General

Astronomical clocks not only show the time and astronomical facts, but are often richly decorated as prestige objects and sometimes additionally equipped with a carillon and a figure play. They can be "a kind of scientific church furniture with a quasi-sacral character".

In addition to showing the movements of the heavens that were currently being researched, they also served to encourage the viewer to reflect more deeply on time and - especially in churches - on their own transience. For example, figure games were used to make these connections clear; this is how one finds the representation of human life from childhood to death, which is run through once every 24 hours.

Some of the clocks also contain elements of sundials or show images of the starry sky analogous to the nocturnal .

Astronomical clocks in Germany and the surrounding area

  • Of the diverse public astronomical clocks in Germany, those in the churches of Northern Germany can best be grouped together. Manfred Schukowski forms the "Hanseuhren family" or the "Baltic Sea clock family" (without clock in Münster , but including clocks in Lund and Danzig ).
  • In southern Germany there was a smaller number of older astrolabe clocks, but more younger zodiac clocks than in northern Germany. In analogy to the term Hanse clocks , the large astronomical clocks of both ages that are mostly attached to town halls in southern German and neighboring foreign cities can be described as imperial city clocks .
  • A specialty that can be found mainly in southern Germany are moon clocks . These are normal clocks that are accompanied by a separate display for the phases of the moon. Zodiac and multi-dial watches are often also equipped with it. One method of display uses a sphere half protruding from a wall and rotating about its axis flush with the wall. Half of it is light (full moon), the other half dark (new moon). Another method involves rotating a disc under an opening in the dial. There are two bright circular areas applied across the diameter, the rest is dark.

Hanse watches

  • Hanse watches

  • Rostock

  • Stralsund

  • Lübeck

  • Muenster

  • Stendal

  • Lund

  • Danzig

These are the following watches:

The Hanse clocks are all located inside church buildings. "They are designed in such a way that their iconographic statements have become part of the Christian-religious furnishings of their places of worship."

The older clocks among them are astrolabe clocks. With the exception of the clock in Münster, they are projected from the north celestial pole (so-called southern projection ). The reverse projected clock in Münster consequently rotates as a whole - also to display the time - counterclockwise.

The zodiac (rete) is no longer turning on the younger clocks or replacement clocks and conversions. These are zodiac clocks in which the so-called "intersection display" by Schukowski has become an analog display. This means that it is not at the intersection of the sun and moon pointers with the rotating and eccentric zodiac, but that their position is read off above the stationary and centric zodiac. The zodiac representing the stars can be mirrored so that the sun and moon hands turn clockwise, as in Stendal. The younger clocks are those in Lübeck, Stendal (later reconstruction), Danzig and Rostock (second clock).

A rotating calendar disc is attached underneath some Hanseatic clocks.

Imperial city clocks

  • Imperial city astrolabe clocks

  • Ulm

  • Prague

  • Bern

Astrolabe clocks

Only the old imperial city of Ulm has a public astrolabe clock . Near foreign cities with an astrolabe clock are Prague , Winterthur (only dial preserved, replica in the tower clock museum of Mindelheim ), Bern and Strasbourg (two no longer preserved versions, today zodiac / multi-dial clock). Except in Strasbourg (in the Münster) all these clocks are / were on town halls and towers.

Zodiac and multi-dial clocks

  • Zodiac dials

  • Esslingen

  • Heilbronn

  • Tübingen

  • Schaffhausen

  • Sion

  • Solothurn

  • Aschaffenburg: 12 o'clock + R zodiac (sun) + moon ball + days of the week (planet symbols), 1957
  • Esslingen : 12 noon + R zodiac (sun, moon) + moon disc + figure play, 16th century
  • Heilbronn : 12 o'clock + R zodiac (sun, moon) and days of the week (planetary gods) + moon disc and pointer for moon age, 16th century.
  • Cologne (Uni): 12 o'clock and moon ball + R zodiac (sun) + planets (planetarium), 1932
  • Munich ( Deutsches Museum ): 12 noon and R zodiac (sun) + days of the week (planetary gods), approx. 1932
  • Tübingen: 12 noon + R zodiac (sun, moon, dragon pointer) + moon disc
  • Schaffhausen ( Fronwagturm ): 12 o'clock and L-zodiac (sun, moon, dragon) and days of the week (planet symbols) + moon ball
  • Sion - town hall tower : 24 o'clock and zodiac / monthly circle (sun and moon) and 60 min + moon ball
  • Solothurn (Red Tower): 2 × 12 o'clock and L-zodiac (sun, moon), 1525
  • Zug ( Zytturm (Zug) ): 12 o'clock and R zodiac with sun and moon and days of the week with planetary gods + moon ball

Abbreviations:
after a + there is another dial
12 or 2 × 12 or 24 o'clock: clock with 12 or 2 × 12 or 24 hour
scale L or R zodiac: left or right circumferential zodiac
(sun, moon, ..): with sun and moon and ..- pointers

Moon clocks (selection)

A moon clock is understood to be an astronomical clock that is mostly mechanically operated and that displays the moon phase display on a separate dial, which is separate from the 12-hour display. The following list lists some cities with a corresponding clock: Bad Schmiedeberg | Goerlitz | Hann. Münden | Marburg | Naumburg | Ochsenfurt | Plauen | Weissenfels

with moon ball:
Bad Tölz | Hanover | Kaufbeuren | Kirchheim / Teck | Markgröningen | Mindelheim | Nuremberg | Sigmaringen

with moon disc:
Bad Biesingen | Heilbronn | Schwäbischhall | St. Georgen | Stuttgart

as equatorial sundial:
in the collection of the Württembergisches Landesmuseum Stuttgart.

Important special astronomical clocks

Great astronomical clocks were made all over Europe, especially between the 14th and 17th centuries. Well-known and important clocks can be found in the following cities:

Astrolabe clocks

Bern

Astrolabe clock in Bern at the Zytgloggeturm ( clock tower), southern projection

In Bern there is the Zytglogge Tower ( Bern German for time bell tower), a clock tower built as a defense and watchtower with city ​​gate in the 13th century , to which an automatic figure play and an astronomical calendar clock were added around 1530. The play equipment includes a crowing rooster, a little court jester and a parade of 7 bears, the heraldic animal of Bern (one for each weekday). High up in the roof of the tower, a gilded knight (Hans von Tann) carved out of wood operates as an hour-striker on the large hour bell. The calendar shows the moon phase, the position of the sun and moon, the constellations and the planetary positions as well as the current month, day, hour and even the name of the day of the week.

Stralsund

Astrolabe clock in the St. Nikolai Church in Stralsund, southern projection

The astronomical clock in Stralsund's St. Nikolai Church is an astrolabe clock from the 14th century in a southern projection. It was damaged in the 16th century and has not been open since then. But it is the only astrolabe clock preserved almost completely in its original condition; only a few parts of the movement are missing.

A special feature of the watch is the self-portrait of its builder Nikolaus Lilienfeld, which is considered the oldest watchmaker portrait in the German-speaking area.

Prague

Astrolabe clock on Prague City Hall, southern projection

The Prague city hall clock is incorporated into the south facade of the old city hall on the Old Town Square . It is an astrolabe clock from the beginning of the 15th century in southern projection. In addition to the time and the astronomical facts that can be displayed with the astrolabe, it shows the Italian or Bohemian hours counted from sunset on a rotating outer ring . Below the astrolabe clock is a calendar disc from the end of the 15th century. The figure games on both sides of the clock were added in the 17th century, while the game with the 12 apostles was placed above the clock behind the two windows in an unknown later time.

In the final days of World War II , the clock suffered severe damage during a German attack, with the town hall completely burned down. Extensive restoration work in 1948 allowed the clock to be restored to its original state. Together with the Old Town Hall, the approximately 600-year-old Prague clock is a national cultural monument and an indispensable part of Old Prague.

Ulm

Astrolabe clock in Ulm (town hall), northern projection, clockwise (mirror-inverted zodiac)
history

The Ulm astronomical clock was probably built into the eastern front of the Ulm town hall around 1520 and overtaken by Isaak Habrecht in 1581 .

In December 1944 the clock was destroyed in a heavy air raid on Ulm . Only the dial with the zodiac ring and the hands remained. A complete renovation took place from 1949 to 1952.

description

The inner part of the astronomical clock in Ulm is an astrolabe clock with the peculiarity that the northern projection usual for astrolabes has also been adopted. This can be seen from the depiction of the horizon as a sink. The view is directed over the northern horizon to the northern sky with the central pole star, whereby in reality the turning of the sky can be observed counterclockwise. In order to obtain a clock with the usual clockwise direction, the projection result was mirrored, whereby the direction of passage on the zodiac was also reversed compared to reality. What remains is the image size of the tropics resulting from a northern projection: the small tropic of Cancer and the large tropic of Capricorn.

Outside the 2 x 12 hour scale, a second, but centrally positioned zodiac rotates together with the eccentric inner one. Such is the hallmark of the later zodiac clocks that no longer contain an astrolabe. But it is no longer turning there. The additional outer 12-hour scale with an additional hour hand (with a hand as a tip) is also characteristic of zodiac clocks.

The inner astrolabe clock has a dragon hand as a third hand in addition to the sun and moon hands . It shows the nodal line of the moon relative to the zodiac. If it is under both the sun and moon hands, a solar or lunar eclipse is possible.

The sun pointer (with sun symbol) is the main pointer for the astrolabic displays: location of the sun on the zodiac (on the inner circle as the date), mean solar time (on the 2 x 12 hour scale) and temporal hour of the day (with the opposite end above the tuft of lines drawn below the horizon).

The moon hand indicates the location of the moon on the zodiac. Its ball, which can be rotated around the pointer rod, clearly shows the phases of the moon .

Commons : Astronomical Clock, City Hall, Ulm  - Collection of images, videos and audio files

Zodiac clocks

St. Marien in Rostock: Astronomical clock (zodiac clock) from 1472

Rostock

An older astrolabe clock, which, like the one in Stralsund, probably came from the same builder Nikolaus Lilienfeld and was probably very similar to this one, was lost. It was replaced in 1472 by a zodiac clock without astrolabic displays. This Rostock clock from 1472 is particularly well documented.

Commons : Astronomical Clock, Marienkirche, Rostock  - collection of images, videos and audio files

Esslingen am Neckar

The old town hall in Esslingen am Neckar was built in 1423 as a department store and wheelhouse. From 1586 to 1589 Heinrich Schickhardt built today's Renaissance gable with the time dial, the astronomical display with three hands: for the movement of the sun and the movement of the moon, plus a dragon hand. This also includes a figure automaton, a representation of the phases of the moon and the imperial eagle, whose wings beat the hours. The Esslingen clockmaker Marx Schwarz received an order from the Esslingen council in 1581 to build a tower clock. He died in 1586 and Jacob Diem from Tübingen completed it in 1589. It ran for 150 years, followed by an eventful history. With the general renovation of the old town hall in 1998, the clockwork disappeared.

When he was rediscovered, an association was formed that collected donations, pushed ahead with the restoration of the monument, commissioned the Turmuhrenbau Ferner company in Meissen in 2006 and took over the entire financing.

The wrought iron clockwork consists almost entirely of original parts. Since the beginning of 2007, the drive has been from the historical clockwork from 1589. This means that the city of Esslingen am Neckar has the oldest wrought-iron tower clock with astronomical gear in Germany, which works like in the Middle Ages with the help of weights and a pendulum.

Special specimens

Strasbourg

The astronomical clock in the Strasbourg Cathedral has in common with the Hanseatic clocks that it is located inside a large church. It is a much more elaborate clock and therefore set up in such a way that it comes into its own better than the Hanseatic clocks. It is located on the eastern wall of the south transept, from which it is clearly visible, and is the third clock built for the Strasbourg Cathedral since the 14th century.

The first clock from 1352/54 - the so-called Dreikönigsuhr - was located opposite the two successors. Like the Hanseatic clocks, it was probably an astrolabe clock and also had a calendar disc under it and figure games above it. It stopped at the beginning of the 16th century and was eventually dismantled. Some parts, including a crowing and wing-flapping rooster - probably the oldest surviving figurine machine - are now in the Strasbourg Museum of Decorative Arts .

Astronomical clock in Strasbourg Cathedral : celestial globe in front of today's third clock with the large lower display part

Christian Herlin , Conrad Dasypodius , the Habrecht brothers and the painter Tobias Stimmer created a much larger, around 18 meter high replacement building, which was completed in 1574 . Its astronomical displays were from top to bottom a moon clock, an astrolabe clock in northern projection, a very large calendar disc and a new celestial globe , also driven by a clockwork , designed by the Strasbourg mathematician Konrad Dasypodius . The globe was inclined according to the latitude of Strasbourg and was surrounded by a horizontal ring that represented the Strasbourg horizon . The Strasbourg meridian was represented by a vertical ring, on which the sidereal time could be read from an hour scale on the celestial equator. The globe revolved around itself on a sidereal day . Together with the globe, two half arcs revolved around the celestial axis , which simulated the movement of the sun and moon in the sky. The sun bar turned a little slower than the globe. It took about 4 minutes more than the globe to complete one revolution (a total of one sunny day ). At its intersection with the ecliptic painted on the globe , the position of the sun in the ecliptic / zodiac was shown. The moon bar turned much slower than the sun bar, so that in about 29½ days it lagged one turn behind it, which is a moon phase period . The passages of the temple / ecliptic intersections through the horizon ring are the moments of sunrise and sunset or moonrise and moonset. In 1788 this clock stopped completely. Some parts were brought to the Strasbourg Museum of Decorative Arts. Some of them were not renewed, but replaced by basically different parts (displays) in today's third clock. The design as a zodiac clock - as with today's second Rostock clock - was skipped.

Astronomical clock in Strasbourg Cathedral

The third Strasbourg astronomical clock was designed in the case of the Dasypodius clock by Jean-Baptiste Schwilgué , built in 1838/43 and still works today. Its astronomical displays are from top to bottom a moon clock, a planetarium, a very large clock with sun and moon hands and a celestial globe also driven by the clockwork. Schwilgué partially adopted the heliocentric view of the world in his watch . So he installed a planetarium in the place of the previous astrolabe clock. Then the earth, together with its moon and together with other planets, circles the still standing sun. The circumferential scale is the zodiac. To read the sign of the zodiac in which the sun is located, you have to aim from the earth symbol over the sun to the edge of the scale. The newly designed clock with sun and moon hands takes the previous place of the calendar disc. This is the part of the clock system with the highest accuracy and the greatest gear effort. The geocentric view of the world is still used here, but it is no longer conveyed in a clear manner like an astrolabe. A zodiac and thus the reference to it does not exist. The display has a 2-by-12-hour dial on which the sun hand shows the true local time in Strasbourg. The equation of time is thus taken into account. An automatically adjusting hand pointing to the left and to the right indicates the sunrise and sunset times. The moon hand indicates the relative position of the moon to the sun. Its drive takes into account several astronomical reasons for the fact that the course of the moon around the earth is rather uneven.

In the celestial sphere even the precession of the earth (one revolution in about 26,000 years) is shown. All in all, Schwilgué has created more of a complex calculating machine , the accuracy of which the displays cannot be recognized by ordinary viewing, than just a clock.

At the bottom left is a moving church calendar that can display all church dates since the introduction of the Gregorian calendar in 1582.

For the less scientifically interested visitors, the clock offers many more details: The revolving apostles, the hourly representation of human life from children to old men, the seven days of the week as planets and the crowing rooster are just some of them.

The best German sources for this watch are the books by 1) Günther Oestmann (1993 and 2000) and 2) Henri Bach and Jean-Pierre Rieb (1992). Another source of their history of the astronomical details of their display is found in Stars and Space (1985).

Commons : Astronomical Clock, Strasbourg Cathedral  - Collection of images, videos and audio files

Besançon

Besançon Astronomical Clock

The clock in Besançon ( France ) was commissioned by Cardinal Mathieu in the years 1858–1860 as a replacement for the clock in the Saint-Jean cathedral, which was no longer working . The city was the French watch mecca. In addition to the local watchmaking industry, many famous Parisian manufacturers (including Louis LeRoi) maintained studios in the fortress city in order to benefit from the excellent skilled workers that this region produced. Chronometer competitions were held at the observatory and a watchmaking school was founded.

Since excellent Swiss watchmakers had also settled in Besançon at the time, fleeing the unrest following the French Revolution , the exceptional execution of this watch was mandatory. In the end, however, the clock was not built in Besançon, but manufactured in Beauvais by the local clockmaker Auguste-Lucien Vérité - for the precision fanatics among the experts, this experienced tower clock manufacturer and engineer was the only option. Vérité pored over the plans and calculations for months; it took Mr. Vérité two and a half years to complete the construction. Choosing a manufacturer from outside the city is by no means a contradiction in terms: In the not-too-distant Swiss town of La Chaux-de-Fonds, a precision tower clock was also installed by Collin from Paris in 1860 in the local temple tower .

In contrast to other astronomical clocks, the Besançon clock is not placed on a wall that can be seen from afar, but in a clock room on the first floor of the bell tower. The countless astronomical displays - a total of 70 dials show, for example, the times in 17 places around the world, the tidal range in various French ports, a perpetual calendar and the leap year cycles - are artfully complemented by popular machines, figure runs and animated dioramas. In total, the watch consists of more than 30,000 mechanical parts; The time is also transferred to the tower clock dials on the outside via cardan shafts.

More astronomical clocks in Europe

Astronomical clock in the choir of Chartres Cathedral
Astronomical clock at the Palace of the Grand Masters in Valletta (Malta) showing the phases of the moon

literature

Web links

Commons : Astronomical Clocks  - Collection of Images, Videos and Audio Files

Individual evidence

  1. ↑ Roger Lehni: The Astronomical Clock of Strasbourg Cathedral. Edition La Goélette, Paris 1992. ISBN 2-906880-21-3 . P. 5.
  2. ^ J. Altermatt: The astronomical console clock from 1609 in the Aarhof Castle in Solothurn. In: Chronométrophilia No 47, winter 1999.
  3. ↑ Manfred Schukowski with the assistance of v. Wolfgang Erdmann u. Kristina Hegner: The Astronomical Clock in St. Marien zu Rostock , 2., ext. u. update Edition Königstein i. Ts. 2010 (= The Blue Books), p. 9
  4. ↑ Manfred Schukowski: Wunderuhren: astronomical clocks in churches of the Hanseatic period. Thomas Helms Verlag, Schwerin 2006. ISBN 3-935749-03-1 .
  5. ↑ Manfred Schukowski with the collaboration of Wolfgang Erdmann and Kristina Hegner: The Astronomical Clock in St. Marien zu Rostock. 2., ext. u. update Edition Königstein i. Ts. 2010 (= The Blue Books), pp. 9–13.
  6. ↑ The moon clock in Sigmaringen .
  7. ↑ The moon clock in Schwäbisch Hall
  8. ^ Manfred Schukowski: Clocks and churches from the Hanseatic era. In: Deutsche Gesellschaft für Chronometrie (DGC), annual publication 2009, list on p. 70
  9. ^ Manfred Schukowski: Clocks and churches from the Hanseatic era. In: German Society for Chronometry (DGC), annual publication 2009, p. 70.
  10. ^ Astrolabe, clock and clock-hand sense
  11. ^ Henry Bach: The three astronomical clocks of the Strasbourg cathedral. M. Schauenburg, 1994. ISBN 3-7946-0297-8 . P. 28 f.
  12. ↑ Ulm's astronomical clock . ed. by the city of Ulm, Text: Wolf-Henning Petershagen, 2010. Accessed November 1, 2017.
  13. ↑ a b c d e Displays and functionality of the Ulm Astronomical Clock ( Memento of the original from April 20, 2006 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. . @1@ 2Template: Webachiv / IABot / basis.ulm.de
  14. ↑ Ulm's astronomical town hall clock on the Internet . Ulm.de. Archived from the original on July 3, 2010. Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved December 12, 2010. @1@ 2Template: Webachiv / IABot / www.ulm.de
  15. ^ The astronomical clock at Ulm City Hall
  16. ^ Manfred Schukowski with the collaboration of Wolfgang Erdmann and Kristina Hegner: The astronomical clock in St. Marien zu Rostock ; 2., ext. u. updated edition Königstein im Taunus, Verlag Langewiesche Nachf., 2010 (= Die Blauen Bücher), ISBN 978-3-7845-1236-5
  17. ^ Database of the Rostock Astronomical Clock
  18. ^ Peter Köhle: The clock at the old town hall in Esslingen. Anton H. Konrad Verlag. ISBN 3-87437-471-8 .
  19. ↑ Roger Lehni: The Astronomical Clock of Strasbourg Cathedral. Éditions la goélette, 1992, p. 5.
  20. ↑ Roger Lehni: The Astronomical Clock of Strasbourg Cathedral. Editions la goélette, 1992, pp. 6-9
  21. ^ Henri Bach: The globe of Dasypodius , in writings of the friends of old clocks, 1979, pp. 19-36
  22. ↑ Roger Lehni: The Astronomical Clock of Strasbourg Cathedral. Éditions la goélette, 1992, illustration on p. 6
  23. ^ Günther Oestmann : The astronomical clock of the Strasbourg cathedral. Function and meaning of a Kosmos model of the 16th century. Publishing house for the history of the natural sciences and technology, Stuttgart 1993. ISBN 3-928186-12-4 .
  24. ^ Henri Bach, Jean-Pierre Rieb, Robert Wilhelm: The three astronomical clocks of the Strasbourg cathedral. Editions Ronald Hirlé, Strasbourg 1992. ISBN 3-7946-0297-8 .
  25. ↑ History and details of the Astronomical Clock in Strasbourg ( Memento of April 28, 2009 in the Internet Archive )
  26. ↑ Virtuální muzeum hodin: 100 years town hall clock in Litomyšl in Czech
  27. ^ City of Olomouc: Astronomical Clock
  28. ↑ Virtuální muzeum hodin: Astronomical Clock Prostějov Czech
  29. ↑ Virtuální muzeum hodin: Town hall clock in Uherský Brod in Czech