Ulugh Beg, the grandson of the great conqueror Timur, was born on the 22nd of March 1394 in Sultaniyeh during a time of massive military expansion. While his grandfather was busy carving out an empire across Persia and India, the young prince was given the name Mīrzā Muhammad Tāraghay, a title that would eventually be overshadowed by the moniker Ulugh Beg, meaning Great Ruler. This name was not merely a label but a declaration of his future authority, echoing the Persian title Amīr-e Kabīr used by Timur himself. As a child, he wandered through the Middle East and India, witnessing the vastness of the world that his family sought to control. After Timur's death, the capital of the empire shifted to Herat, but the sixteen-year-old Ulugh Beg was appointed governor of the former capital, Samarkand, in 1409. By 1411, he had become the sovereign ruler of all Mavarannahr, setting the stage for a reign that would blend the brutality of a conqueror with the precision of a scientist.
Building A Center Of Learning
In 1428, Ulugh Beg constructed an enormous observatory in Samarkand, one of the finest in the Islamic world and the largest in Central Asia. Lacking telescopes, he increased the accuracy of his measurements by building a massive sextant known as the Fakhri sextant, which had a radius of about 50 meters and an optical separability of 180 seconds of arc. This instrument was the largest at the observatory and was used to measure the transit altitudes of stars, allowing for the determination of their declination. The observatory housed many other astronomical instruments, but the Fakhri sextant remains the most well-known. Using these tools, Ulugh Beg composed a star catalogue consisting of 1018 stars, which was eleven fewer than the catalogue of Ptolemy but more accurate. He utilized dimensions from al-Sufi and based his work on a new analysis that was autonomous from the data used by Ptolemy. Throughout his life, he realized that there were multiple mistakes in the work and subsequent data of Ptolemy that had been in useThe Giant Sextant And The Star Catalogue
for many years. In 1437, he compiled the Zij-i-Sultani of 994 stars, generally considered the greatest star catalogue between those of Ptolemy and Tycho Brahe. This work stands alongside Abd al-Rahman al-Sufi's Book of Fixed Stars and was first edited by Thomas Hyde at Oxford in 1665 under the title Jadāvil-i Mavāzi' Sāvit.
Ulugh Beg's measurements were so precise that they remained unmatched for centuries. In 1437, he determined the length of the sidereal year as 365.2570370 days, an error of only 58 seconds. He used a 50-meter high gnomon to make these measurements over the course of many years. This value was improved by 28 seconds in 1525 by Nicolaus Copernicus, who appealed to the estimation of Thabit ibn Qurra, which had an error of only 2 seconds. However, Ulugh Beg later measured another more precise value of the tropical year as 365 days, 5 hours, 49 minutes, and 15 seconds, which has an error of 25 seconds, making it more accurate than Copernicus's estimate which had an error of 30 seconds. He also determined the Earth's axial tilt as 23 degrees, 30 minutes, and 17 seconds, which in decimal notation converts to 23.5047 degrees. In mathematics, Ulugh Beg wrote accurate trigonometric tables of sine and tangent values correct to at least eight decimal places, showcasing his mastery of both observation and