Al-Battani, archaically Latinized as Albategnius, was an Arab Muslim astronomer, astrologer, geographer and mathematician, who lived and worked for most of his life at Raqqa, now in Syria. He is considered to be one of the greatest and most famous of the astronomers of the medieval Islamic world. 850 – 930; died at about 80. Alive at the same time as Alfred the Great, Farabi, Rudaki, Abu Bakr al-Razi, and Al-Kindi. Wiki link