Nur ad-Din al-Bitruji

Nur ad-Din al-Bitruji (also spelled Nur al-Din Ibn Ishaq Al-Betrugi and Abu Ishâk ibn al-Bitrogi; another spelling is al Bidrudschi) (known in the West by the Latinized name of Alpetragius) (died c. 1204) was an astronomer and a Qadi from Al-Andalus. Despite his limited knowledge of Ptolemy's Almagest, al-Biṭrūjī was the first astronomer after Ptolemy to present a non-Ptolemaic astronomical system as an alternative to Ptolemy's models. Another original aspect of his system was that he proposed a physical cause of celestial motions.