A Look at Ulug Beg by Kevin Krisciunas

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]

According to Afghanland.com's sources, A principal source of our information about the astronomical activity at Samarkand is a letter of one Ghiyath al-Din Jamshid al-Kashi (d. 1429), which is available in Turkish and English (see Sayili 1960). This letter, originally in Persian, was written in 1421 or 1422. From it we deduce that serious astronomical activity began in Samarkand in 1408-10, and that the construction of Ulugh Beg's observatory was begun in 1420. Amongthe astronomers known to have been active at Samarkand, we know only a few by name, but according to al-Kashi there were sixty or seventy scholars at the madrasa who were well enough versed in mathematics to participate in some capacity in the astronomical observations and/or seminars.

The observations were carried out systematically from 1420 to 1437. While observatories today are expected to carry on indefinitely, this was not the case in olden times. Rather, observations were carried out, for example, to update tables of planetary motions in order to predict their future positions. al-Kashi tells us (see Sayili 1960, p.106):

As to the inquiry of those who ask why observations are not completed in one year but require ten or fifteen years, the situation is such that there are certain conditions suited to the determination of matters pertaining to the planets, and it is necessary to observe them when these conditions obtain. It is necessary, e.g., to have two eclipses in both of which the eclipsed parts are equal and to the same side, and both these eclipses have to take place near the same node. Likewise, another pair of eclipses conforming to other specifications is needed, and still other cases of a similar nature are required. It is necessary to observe Mercury at a time when it is at its maximum morning elongation and once at its maximum evening elongation, with the addition of certain other conditions, and a similar situation exists for the other planets.

 

Comments:

I enjoyed your article regarding Ulugh Beg's Obseravtory in Afghanland.com.

 

In support of your article I wanted to say that I, as a student of a Medical school in Ukraine, visited Samarkand in year 1979. I saw Ulugh Beg's Observatory and his hand written notes in Persian script. One open page under the glass in the museum very clearly stated: Despite the general thought, this is the Earth that orbits the Sun, not Sun orbiting the Earth. And I understand it was an independent discovery of this great Central Asian scientist who lived prior to Galeleo. (I hope document was not faked by Russians at that time) 

  

Saif Nasafi