Al-Kharaqī

Abū Muḥammad 'Abd al-Jabbār al-Kharaqī, Persian: بهاءالدین ابوبکر محمد بن احمد بن ابوبشر also Al-Kharaqī (1084-1158) was a Persian astronomer and mathematician of the 12th century, born in Kharaq near Merv. He was in the service of Sultan Sanjar at the Persian Court. Al-Kharaqī challenged the astronomical theory of Ptolemy in the Almagest, and established an alternative theory of the spheres, imagining huge material spheres in which the planets moved inside tubes. He later wrote at-Tabṣıra fî ʿilmi’l-hayʾa as a second edition to his well-known book Muntahā al-idrāk fī taqāsīm al-aflāk in which he removed some parts and reshaped its structure as two parts instead of three.