page_title: Prague astronomical clock
section_title: Zodiacal ring
hierarchical_section_title: Prague astronomical clock / Astronomical dial / Zodiacal ring
caption_attribution_description: Deutsch: Die Prager Rathausuhr (am Altstädter Rathaus in Prag) wurde 1410 vom Uhrmacher Nikolaus von Kaaden nach Plänen des Professors für Mathematik und Astronomie Jan Schindel gebaut und ist die älteste funktionierende Astronomische Uhr der Welt. English: The Prague astronomical clock (in Old Town Square) was installed in 1410 by clock-makers Mikuláš of Kadaň and Jan Šindel, and is the oldest functioning Astronomical clock in the world. Français&#160;: L'horloge astronomique de Prague (Place de la Vieille Ville) a été installée en 1410 par les horlogers Mikuláš of Kadaň et Jan Šindel, et est l'horloge astronomique la plus ancienne fonctionnant dans le monde. 日本語: プラハの天文時計 (旧市街広場) は1410年に時計職人カダンのミクラシュ (Mikuláš of Kadaň) とヤン・シンデルにより取り付けられた。現在作動中の天文時計では世界最古のものである。 Latina: Hoc est Horologium Astronomicum Pragense, taenia mediaevalis in urbe Praga sita. Horologium astronomicum primum inducebatur anno 1410, et id facit horologium astronomicum tertium veterrimum in Tellure, atque veterrimum etiamnunc fungens est.
context_page_description: The Prague Astronomical Clock, or Prague Orloj, is a medieval astronomical clock located in Prague, the capital of the Czech Republic.
  The clock was first installed in 1410, making it the third-oldest astronomical clock in the world and the oldest clock still operating.
context_section_description: Inside the large black outer circle lies another movable circle marked with the signs of the zodiac which indicates the location of the Sun on the ecliptic. The signs are shown in anticlockwise order. In the photograph accompanying this section, the Sun is currently moving anticlockwise from Cancer into Leo.
  The displacement of the zodiac circle results from the use of a stereographic projection of the ecliptic plane using the North pole as the basis of the projection. This is commonly seen in astronomical clocks of the period.
  The small golden star shows the position of the vernal equinox, and sidereal time can be read on the scale with golden Roman numerals. The zodiac is on the 366-tooth gear inside the machine. This gear is connected to the sun gear and the moon gear by a 24-tooth gear.
caption: Astronomical dial
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