Quṭb al-Dīn Shīrāzī and His Observations on Ptolemy’s Lunar Model
Dr. Kaveh Niazi
(Stanford Online High School)
Quṭb al-Dīn Shīrāzī (d. 1311 CE) completed his astronomical text Ikhtiyārāt-i muẓaffarī in 1282 CE. A richly detailed work composed in Persian, the Ikhtiyārāt covers much of the material appearing in his Arabic text Nihāyat al-idrāk fī dirāyat al-aflāk (completed in 1281 CE.). Intriguingly, Shīrāzī did include in the Ikhtiyārāt material that is missing from its companion. One such passage treats the concept of the prosneusis point as defined for the Ptolemaic lunar model in the Almagest. An examination of Shīrāzī’s discussion of the prosneusis point, both in comparison to related discussions on the physics of planetary orbs, and in the context of Shīrāzī’s more general cosmological discussions in other parts of the Ikhtiyārāt, offers a window to Shīrāzī’s approach to theoretical astronomy, while highlighting, as well, his approach to the authoring of technical texts for astronomy students.