The intellectual legacy of the brilliant astronomer Ulugh Beg

by Guest Wed Oct 25, 2017 5:00 am

Muhammed Taragai Ulugh Beg (1394-1449) was a Turk who ruled the province of Transoxiana (Maverannahr), a region situated between the River Oxus (Amu Darya) and the River Jaxartes (Syr Darya), the principal city of which was Samarkand. Ulugh Beg's grandfather was the famous conqueror Timur (1336-1405). Ulugh Beg became the ruler of Transoxiana in 1447 upon the death of his father. But his rule was of short duration. Two years later he was killed by an assassin hired by his son 'Abd al Latif.

Were it only for his role as prince, viceroy, and martyr, few scholars would know of Ulugh Beg. But his memory lives on because he was an observatory builder, patron of astronomy, and astronomer in his own right. He was certainly the most important observational astronomer of the 15th century. He was one of the first to advocate and build permanently mounted astronomical instruments. His catalogue of 1018 stars (some sources count 1022) was the only such undertaking carried out between the times of Claudius Ptolemy (ca. 170 A.D.) and Tycho Brahe (ca. 1600). And, as we shall briefly discuss here, his attitude towards scientific endeavors was surprisingly modern. The administration of Transoxiana was the responsibility of Ulugh Beg's father for most of Ulugh Beg's life. The prince had the opportunity (and the inclination) to pursue scholarly matters. His interest in astronomy dates from an early age, when he visited the remains of the Maragha Observatory, made famous by the astronomer Nasir al-Din al-Tusi (1201-74). The principal accomplishment at Maragha was the Zij-i ilkhani, or Ilkhanic Tables.[2]...

At Samarkand it was the practice for a larger number of people to discuss the results. In modern terms, this is like peer review, the purpose of which is to eliminate sources of error and to ensure the health of the observational program. Ulugh Beg himself has allowed that in scientific questions there should be no agreeing until the matter is thoroughly understood and that people should not pretend to understand in order to be pleasing. Occasionally, when someone assented to His Majesty's view out of submission to his authority, His Majesty reprimanded him by saying 'you are imputing ignorance to me.' He also poses a false question, so that if anyone accepts it out of politeness he will reintroduce the matter and put the man to shame.[5]

The foreword to Ulugh Beg's Zij contains four parts: 1) the chronology, describing various systems of time reckoning; 2) practical astronomy (how observations are made and used); 3) the apparent motions of the Sun, Moon, and planets, based on a geocentric system of the universe; and 4) astrology. Besides the tables of motions of the Sun, Moon, and planets,Ulugh Beg's Zij was significant for its catalogue of about 1000 stars, giving their names and ecliptic coordinates. In an appendix to this paper I give a list of published works that contain all or part of Ulugh Beg's Zij.[6] In Flamsteed's Historia Coelestis Britannica (1725) and Baily's 1843 treatise we can directly compare Ulugh Beg's positions with those of Ptolemy,Tycho Brahe, and others. With modern stellar positions, proper motions, and an accurate treatment of precession, it would be interesting to make a statistical analysis of, say, the 100 brightest stars, to see how these catalogues compare as to average accuracy.[7]...

If the activities in Samarkand influenced European ones, why does Ulugh Beg only get cursory mention (on pp. 328 and 347, but not in the index) of Dreyer's classic 1890 biography of Tycho Brahe? In Thoren's even more authoritative 1990 biography of Tycho there is no mention of Ulugh Beg at all. It was work such as Tycho's, not Ulugh Beg's, that led in turn to the efforts at Greenwich (founded 1675), Pulkovo (founded 1839), and the United States Naval Observatory (founded 1844), among other institutions, and these modern, national, facilities did not need or use Ulugh Beg's work as a fundamental component of the construction of accurate star catalogues. Yet, to be fair, astronomers and historians have found many uses for ancient and medieval observations, such as studies of the spin down rate of the Earth, studies of the motion of the Moon and planets, and the dating of historical events. Ulugh Beg's observations being the best of their century allow them to stand as a permanent observational archive for our benefit. For example, Shcheglov (1977) has recently used information from the modern excavation of Ulugh Beg's large meridian instrument for a study of continental drift.

The most direct influence of the Samarkand Observatory was on the construction of the five observatories, or Jantar Mantars, built by Maharajah Jai Singh (1686-1743) in India. Jai Singh was a Hindu prince in the court of a Muslim Mogul emperor. These observatories were built at New Delhi, Ujjain, Mathura, Varanasi, and Jaipur. The largest instrument was 27 meters high. For more information see Kaye (1918), Mayer (1979), Sharma (1987), and Bedding (1991). While recognition of Ulugh Beg's contributions to astronomy was delayed, an extensive body of information now exists on the activity of his observatory in Samarkand.[8] We now know that at the time Ulugh Beg's observatory flourished it was carrying out the most advanced observations and analysis being done anywhere. In the 1420's and 1430's Samarkand was the astronomical capital of the world. As such it is deserving of further study.

http://vlib.iue.it/carrie/texts/carrie_books/paksoy-2/cam6.html

by Guest Wed Oct 25, 2017 5:02 am

i should add that a direct descendant of Ulugh Beg was the Mughal Emperor Babur. Babur has written very appreciatively about Ulugh Beg in his autobiography, the Baburnama.

The intellectual legacy of the brilliant astronomer Ulugh Beg

The intellectual legacy of the brilliant astronomer Ulugh Beg

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