Hulagu Khan believed that many of 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 astronomical tables were 250 years old, Hulagu gave permission to build a new observatory in a place of al-Tusi's choice (he chose
Maragheh). A number of other prominent astronomers worked with al-Tusi there, including
Muhyi al-Din al-Maghribi,
Qutb al-Din al-Shirazi,
Mu'ayyid al-Din al-'Urdi from
Damascus. Furthermore, the influence of
Chinese astronomy was brought by
Fao Munji, whose 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 of
Abaqa Khan, Hulagu's son, and named after the patron of the observatory. They were popular until the 15th century. Some Islamic astronomical tables such as the ''Zij-i Al-`Ala'i
of Abd-Al-Karim al-Fahhad and the Zij al-Sanjari'' of
al-Khazini were translated into
Byzantine Greek by
Gregory Chioniades and studied in the
Byzantine Empire. Chioniades himself had studied under
Shams ad-Din al-Bukhari, who had worked at the famous
Maragheh observatory after the death of al-Tusi. ==See also==