Zij-i Ilkhani
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Zij-i Ilkhani or Ilkhanic Tables (literal translation: "The Ilkhan Stars", after ilkhan Hulagu, who was the patron of the author at that time) is a book with astronomical tables of planetary movements by a Persian astronomer Nasir al-Din al-Tusi. It was written in Persian language and later translated into Arabic.
The books contains tables for calculating the positions of the planets and the names of the stars. It is based on the observations of planets over 12 years in Maragheh 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 of Copernicus.
The book also describes a method of interpolation between the observed positions, which in modern terms may be described as a second-order interpolation scheme.
[edit] History
Hulagu Khan believed that many his military successes were due to the advice of astronomers (who were also astrologers), especially of al-Tusi. Therefore when al-Tusi complained that his astromical tables are 250 years old, Hulagu gave a permission to build a new observatory in a place of al-Tusi's choice (it was Maragheh). A number of other prominent astronomers worked with al-Tusi there, such as Muhyi al-Din al-Maghribi, Mu'ayyid al-Din al-'Urdi, from Damascus, Qutb al-Din al-Shirazi, and Hulagu's Chinese astronomer Fao Munji (?) whose Chinese astronomical experience brought improvements to Ptolemaic system used by al-Tusi and traces of the Chinese system may be seen in Zij-i Ilkhani. The tables were published during the reign of Abaqa Khan, Hulagu's son, and named after the patron of the observatory. They were popular untill the 15th century.
[edit] 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
- Javad H. Zadeh,"A Second Order Interpolation Scheme Described in the Zij-i Ilkhani ", Historia Mathematica (1985) vol. 12, pp. 56-59,
