d. after 961

Also known as Abu Jafar Muhammad ibn al-Hasan al-Khurasani, or Abu Jafar al-Khazin, his writings may be the work of two separate people of the same name. Al-Khazin wrote on number theory and astronomy, but only two books survive intact. The astronomical work includes details of the astrolabe and other astronomical instruments. The mathematical work is a commentary on Book 10 of Euclid's Elements, and contains work on spherical trigonometry related to planetary motion. He was also an astrologer, and theorized a clever model of the solar system.