Ibn Yunus

Abu al-Hasan 'Ali ibn Abi al-Said 'Abd al-Rahman ibn Ahmad ibn Yunus ibn Abd al-'Ala al-Sadafi al-Misri was an important Egyptian astronomer and mathematician, whose works are noted for being ahead of their time, having been based on meticulous calculations and attention to detail. He is one of the famous Muslim astronomers who appeared after Al-Battani and Abu al-Wafa' al-Buzjani, and he was perhaps the greatest astronomer of his time. Because of his brilliance, the Fatimids gave him generous gifts and established an observatory for him on Mount Mokattam near Fustat. Al-Aziz Billah ordered him to make astronomical tables, which he completed during the reign of Al-Hakim bi-Amr Allah, son of Al-Aziz, and called it al-Zij al-Kabir al-Hakimi. The crater Ibn Yunus on the Moon is named after him.