The Book of Remedies from Deficiencies in Setting Up Marble Sundials
This work is a treatise for timekeepers (singular muwaqqit), and discusses the telling of time from such astronomical observations as the sun’s angle of inclination (mayl), altitude (irtifā‛), as well as the direction (samt) and length of cast shadows (zill). In 14 chapters, the author goes through methods for the computation of these factors, determination of the direction of prayer (qibla), and time of the day. He observes that using instruments (ālāt), such as markings on the ruler (mistara) and the compass (bargār, from the Persian pargār), and geometric methods are straightforward, but inaccurate nevertheless. Therefore, he sets out to explain the arithmetical (hisāb) aspects of astronomical measurements. His work contains numerous geometric diagrams and is rich with tables based on those prepared by Abu al-‛Abbās Ahmad b. Muhammad b. Kathīr al-Farghānī, also known in the history of astronomy as Alfraganus. The latter had visited Egypt in 861 (247 A.H.) to supervise the construction of the Nilometer. The scribe’s name is Ramadān b. Sālih b. ‛Umar b. Ḥijāzī b. ‛Umar al-Ḥāfiz al-Muqrī, known as Safitī.
Shihāb al-Dīn Ahmad b. ‛Umar b. Ismā‛īl b. Muhammad b. Abī Bakr al-Sūfī (Ibn al-Sūfī) (Died 719 AH / 1319 AD)
Title in Original Language
شفاء الأسقام فى وضع الساعات على الرخام
Type of Item
130 leaves; 12.5 x 17 centimeters
Last updated: September 29, 2014