Kidinnu

Kidinnu (also Kidunnu , Kidenas , Cidenas , Kidynas , * possibly around 400 BC in Babylon ; † possibly August 14, 330 BC ) was a Chaldean astronomer and mathematician.

An astronomer by that name is mentioned in various ancient cuneiform, Greek, and Latin scripts, but it is unclear whether these all refer to the same person. The date of death August 14, 330 BC. BC comes from a Babylonian astronomical cuneiform tablet, which states that "ki-di-nu was killed with the sword on this day".

Kidinnu was the most important successor of Nabu-rimanni and worked like him on the development of the exact Babylonian lunar calendar .

Standardized Babylonian Calendar

At least since 503 BC BC, under Darius I , the standardized Babylonian lunar calendar applied, which was adapted to a nineteen-year cycle. In years 3, 6, 8, 11, 14 and 19 the month of Adaru II was inserted ; in the 17th year, however, as the thirteenth month of Ululu II . The beginning of the year was always close to the spring equinox . Claudius Ptolemy mentions in his astronomical notes that the Greek astronomers Meton and Euktemon adopted the system of the standardized Babylonian calendar as a basis and adapted it to the Attic calendar (see Meton cycle ).

Kidinnu later calculated the dates of the solar year , which still form the basis of our calendar today. The Kidinnu model also found its way into the Jewish calendar and has remained unchanged since then.

Further discoveries by Kidinnu

Another discovery of Kidinnu is recorded in the tables of Claudius Ptolemy . Kidinnu's achievement was his observation and realization that the duration of 251 synodic months corresponds to the duration of 269 anomalistic months . The associated calculations were difficult to carry out at that time, as the distance between the moon and the earth varies between 356,000 and 407,000 kilometers; perception with the naked eye is associated with great difficulties.

According to Pliny, Kidinnu determined the maximum elongation of the planet Mercury from the sun to be 22 °. The Roman astrologer Vettius Valens used Hipparchus' data for the sun, but Kidinnu and Soudines for the lunar orbit . The Mondephemerids of the Babylonian System B are also traced back to Kidinnu.

literature

• Hermann Hunger u. a .: Handbuch der Orientalistik, Department 1, Vol. 44 - Astral sciences in Mesopotamia - , Brill, Leiden 1999, ISBN 90-04-10127-6 , (texts in English, French, German and Aramaic)
• Jean Meeus : Astronomical Algorithms , u. a. Applications for Ephemeris Tool 4,5 Barth Leipzig 2nd edition 2000, ISBN 3-335-00400-0

Web links

• Date of death of Kidinnu
• Kidinnu

Remarks