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 Arab and Egyptian astronomer and mathematician,. The Fatimids gave him 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. 950 – 958; died at about 8. Wiki link