- Zij-i Ilkhani
Zij-i Ilkhani or Ilkhanic Tables (literal translation: "The
Ilkhan Stars", after ilkhanHulagu , who was the patron of the author at that time) is a book with astronomical tables ofplanet ary movements by a Persian astronomerNasir al-Din al-Tusi in collaboration with other astronomers at theMaragha observatory . It was written in Persian and later translated into Arabic.The book contains tables for calculating the positions of the planets and the names of the stars. It included data derived from the observations of the stars and planets over 12 years in the Maragha observatory, completed in 1272. The planetary system of Tusi was the most advanced of his period and was used extensively until the development of the
heliocentric model in the time ofCopernicus .The book also describes a method of
interpolation between the observed positions, which in modern terms may be described as asecond-order interpolation scheme.History
Hulagu Khan believed that many his military successes were due to the advice of astronomers (who were also
astrologer s), especially of al-Tusi. Therefore when al-Tusi complained that his astromical tables were 250 years old, Hulagu gave permission to build a new observatory in a place of al-Tusi's choice (he choseMaragheh ). A number of other prominent astronomers worked with al-Tusi there, such asMuhyi al-Din al-Maghribi ,Mu'ayyid al-Din al-'Urdi , fromDamascus ,Qutb al-Din al-Shirazi , and Hulagu's Chinese astronomerFao Munji whose Chinese astronomical experience brought improvements to Ptolemaic system used by al-Tusi - traces of the Chinese system may be seen in "Zij-i Ilkhani". The tables were published during the reign ofAbaqa Khan , Hulagu's son, and named after the patron of the observatory. They were popular until the 15th century.ee also
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Zij References
*Nasir al-Din al-Tusi, "Zij-i Ilkhani",
British Museum , MS Or.7464.
*J. A. Boyle, "The Longer Introduction to the "Zij-i Ilkhani" of Nasir ad-Din Tusi",Journal of Semitic Studies (1963) 8(2), pp.244-254
*E. S. Kennedy, "A Survey of Islamic Astronomical Tables", Transactions of the American Philosophical Society, (1956) 46(2), pp. 3, 39-40.
*Javad H. Zadeh,"A Second Order Interpolation Scheme Described in the "Zij-i Ilkhani" ",Historia Mathematica (1985) vol. 12, pp. 56-59.
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