Persian Astronomical Tables (Zij)

Timeline

1. c. 800–900Baghdad · BaghdadAl-Khwarizmi compiled the Zij al-Sindhind, combining Indian and Greek astronomical parameters; al-Battani's Zij al-Sabi further improved the accuracy of planetary position and rising/setting tables, establishing the standard format and computational methods of astronomical tables in the Islamic world.
2. c. 1000–1150Isfahan · IsfahanOmar Khayyam directed the revision of the Zij-i Malik-i Shahi, correcting precession and planetary orbit parameters with observational data; astronomers across Persia and Central Asia widely transcribed and used various Zij, forming a tradition of table systems tailored to regional latitudes.
3. c. 1211–1220Khorasan–Khwarazm · KhorasanOn the eve of the Mongol invasions in the early 13th century, Persian and Central Asian scholars were still using and transcribing various Zij for calendar computation at courts and observatories; these tables supported local Islamic calendar, prayer time tables, and agricultural seasonal calculations, serving as carriers of everyday astronomical practice in the Islamic world.
4. c. 1250Maragha · MaraghaNasir al-Din Tusi compiled the Zij-i Ilkhani at the Maragha Observatory, integrating earlier Persian Zij traditions with new observational results; observatories in Samarkand, Tashkent, and elsewhere continued to produce ephemerides in the Zij format, which influenced European astronomy through translation.