Abu Ali al-Hasan al-Marrakushi

Abu Ali al-Hasan al-Marrakushi was a distinguished Moroccan astronomer and mathematician born in Marrakesh in 1281 CE. Raised in the cosmopolitan intellectual environment of Morocco, he received a thorough grounding in the mathematical and astronomical sciences before eventually making his way to Cairo, the vibrant capital of Mamluk Egypt, where he would produce his most enduring work.

Al-Marrakushi's crowning achievement was his encyclopaedic treatise known as the Jami' al-Mabadi' wa'l-Ghayat fi 'Ilm al-Miqat, composed around 1282 CE. This exhaustive compendium on mathematical astronomy and timekeeping covered spherical trigonometry, sundial theory, the construction and use of astrolabes, and the determination of prayer times — subjects that were of vital practical importance in the Islamic world. The work compiled, refined, and extended centuries of earlier Islamic astronomical knowledge into a single authoritative reference that specialists would consult for generations.

His meticulous descriptions of instrument construction set new standards of precision. He catalogued dozens of varieties of sundials, explained the geometry underlying each design, and provided tables of breathtaking accuracy for use across different latitudes. His treatment of the astrolabe was equally thorough, encompassing both the theory of stereographic projection and the practical craft of the maker.

Al-Marrakushi spent his later years in Cairo, where he died around 1320 CE. Though he worked at the intersection of science and religious observance — computing prayer times and qibla directions — his mathematical rigour transcended purely devotional aims and advanced pure astronomy as a discipline. His Jami' remained a standard reference in Islamic astronomical literature throughout the medieval and early modern periods, and modern historians of science regard him as among the most technically accomplished astronomers of the thirteenth and fourteenth centuries.