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H-M synthesis: The influence of Ulugh Beg, Babur's great ancestor, on Indian Astronomy

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H-M synthesis: The influence of Ulugh Beg, Babur's great ancestor, on Indian Astronomy Empty H-M synthesis: The influence of Ulugh Beg, Babur's great ancestor, on Indian Astronomy

Post by Guest Fri Mar 24, 2017 7:57 pm

It is well known that Babur was a direct descendant of Timur (Tamerlane) on his father's side. What is not so well known is that Ulugh Beg was Timur's grandson. Babur has written appreciatively about Ulugh Beg in his autobiography.

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1. Ulugh Beg's [astronomical] 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

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2. Initially, Sawai Jai Singh started out using brass instruments but soon abandoned the idea when he realized the presence of several flaws inherent to the small size of the instruments. This resulted in the destabilization of their axes and the consequent displacement of the centre.

Gathering his inspiration from the 15th century Afghani ruler Ulugh Begh’s observatory at Samarkand, Uzbekistan, the idea of building massive masonry instruments favoured Jai Singh’s architectural tastes and apparently promised to be more accurate because of sheer size.

The Delhi observatory was eventually completed in 1724 and was believed by the Indians to be an ingenious creation attributed solely to Jai Singh. However, this is now known not to be the case. The construction of the Jantar Mantar was in actuality adopted from Samarkand. At least two of the instruments at Delhi (viz. the Rama Yantra and the Samrat Yantra) took on strong semblances to those of its Uzbekistani antecedent. The only marked differences are in their size, inner construction details and the external surfaces of the instruments; the basic concepts in building style are essentially the same.


http://www.math.nus.edu.sg/aslaksen/gem-projects/hm/0203-1-07-jantar_mantar.pdf

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3. See also: https://depts.washington.edu/silkroad/cities/uz/samarkand/obser.html

and http://www.centralasia-adventures.com/en/sights/observatory_of_ulughbeks.html

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Last edited by Rashmun on Fri Mar 24, 2017 8:04 pm; edited 1 time in total

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H-M synthesis: The influence of Ulugh Beg, Babur's great ancestor, on Indian Astronomy Empty Re: H-M synthesis: The influence of Ulugh Beg, Babur's great ancestor, on Indian Astronomy

Post by Guest Fri Mar 24, 2017 8:04 pm

Ulugh Beg was primarily a scientist, in particular a mathematician and an astronomer. However, he certainly did not neglect the arts, writing poetry and history and studying the Qur'an. In 1417, to push forward the study of astronomy, Ulugh Beg began building a madrasah which is a centre for higher education. The madrasah, fronting the Rigestan Square in Samarkand, was completed in 1420 and Ulugh Beg then began to appoint the best scientists he could find to positions there as lecturers.

Ulugh Beg invited al-Kashi to join his madrasah in Samarkand, as well as around sixty other scientists including Qadi Zada. There is little doubt that, other than Ulugh Beg himself, al-Kashi was the leading astronomer and mathematician at Samarkand. Letters which al-Kashi wrote to his father have survived. These were written from Samarkand and give a wonderful description of the scientific life there. The contents of one of these letters has only recently been published, see [5].

In the letters al-Kashi praises the mathematical abilities of Ulugh Beg but of the other scientists in Samarkand, only Qadi Zada earned his respect. Ulugh Beg led scientific meetings where problems in astronomy were freely discussed. Usually these problems were too difficult for all except al-Kashi and the letters confirm that al-Kashi was the closest collaborator of Ulugh Beg at his madrasah in Samarkand.

In addition to the madrasah, Ulugh Beg built an observatory at Samarkand, the construction of this beginning in 1428. The Observatory, which was circular in shape, had three levels. It was over 50 metres in diameter and 35 metres high. The director of the Observatory was Ali-Kudschi, a Muslim astronomer. Al-Kashi and other mathematicians and astronomers appointed to the madrasah also worked at Ulugh Beg's Observatory.

Among the instruments specially constructed for the Observatory was a quadrant so large that part of the ground had to be removed to allow it to fit in the Observatory. There was also a marble sextant, a triquetram and an armillary sphere. The achievements of the scientists at the Observatory, working there under Ulugh Beg's direction and in collaboration with him, are discussed in detail in [4]. This excellent book records the main achievements which include the following: methods for giving accurate approximate solutions of cubic equations; work with the binomial theorem; Ulugh Beg's accurate tables of sines and tangents correct to eight decimal places; formulae of spherical trigonometry; and of particular importance, Ulugh Beg's Catalogue of the stars, the first comprehensive stellar catalogue since that of Ptolemy.

This star catalogue, the Zij-i Sultani, set the standard for such works up to the seventeenth century. Published in 1437, it gives the positions of 992 stars. The catalogue was the results of a combined effort by a number of people working at the Observatory including Ulugh Beg, al-Kashi, and Qadi Zada. As well as tables of observations made at the Observatory, the work contained calendar calculations and results in trigonometry.

The trogonometric results include tables of sines and tangents given at 1° intervals. These tables display a high degree of accuracy, being correct to at least 8 decimal places. The calculation is built on an accurate determination of sin 1° which Ulugh Beg solved by showing it to be the solution of a cubic equation which he then solved by numerical methods. He obtained

sin 1° = 0.017452406437283571
The correct approximation is
sin 1° = 0.017452406437283512820
which shows the remarkable accuracy which Ulugh Beg achieved.

Observations made at the Observatory brought to light a number of errors in the computations of Ptolemy which had been accepted without question up to that time. Data from his Observatory allowed Ulugh Beg to calculate the length of the year as 365 days 5 hours 49 minutes 15 seconds, a fairly accurate value. He produced data relating to the Sun, the Moon and the planets. His data for the movements of the planets over a year is, like so much of his work, very accurate [1]:-

... the difference between Ulugh Beg's data and that of modern times relationg to [Saturn, Jupiter, Mars, Venus] falls within the limits of two to five seconds.

http://www-groups.dcs.st-and.ac.uk/history/Biographies/Ulugh_Beg.html

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