Al-Battani
Al-Battani (ca. 850-923) arab astronomer (latinized Albategnius, Albategni, Albatenius; full name Abū ʿAbdullāh Muḥammad ibn Jābir ibn Sinān ar-Raqqī al-Ḥarrani aṣ-Ṣabiʾ al-Battānī), born in Harran near Urfa. His epithet as-Sabi suggests that among his ancestry were members of the Sabian sect who worshipped the stars.
Al Battani worked in ar-Raqqah in Syria. His most important work is the Kitāb az-Zīj ('the book of tables'). In 57 chapters, Al-Battani treats the division of the celestial sphere, and introduces mathematical tools that form the basis of modern trigonometry. He also calculated the values for the precession of the equinoxes (54.5" per year) and the inclination of Earth's axis (23° 35').
The Kitāb az-Zīj, by way of latin translation by Plato Tiburensis in 1116 (printed 1537), had great influence on european astronomy.