 Opening verses of Tantrasamgraha (in Devanagari) | |
| Author | Nilakantha Somayaji |
|---|---|
| Country | India |
| Language | Sanskrit |
| Subject | Astronomy/Mathematics |
Publication date | 1500-01 CE |
Tantrasamgraha,[1][2] or Tantrasangraha,[3] (literally, A Compilation of the System) is an important astronomical treatise written by Nilakantha Somayaji, an astronomer/mathematician belonging to the Kerala school of astronomy and mathematics. The treatise was completed in 1501 CE. It consists of 432 verses in Sanskrit divided into eight chapters.[4] Tantrasamgraha had spawned a few commentaries: Tantrasamgraha-vyakhya of anonymous authorship and Yuktibhāṣā authored by Jyeshtadeva in about 1550 CE. Tantrasangraha, together with its commentaries, bring forth the depths of the mathematical accomplishments the Kerala school of astronomy and mathematics, in particular the achievements of the remarkable mathematician of the school Sangamagrama Madhava. In his Tantrasangraha, Nilakantha revised Aryabhata's model for the planets Mercury and Venus. According to George G Joseph his equation of the centre for these planets remained the most accurate until the time of Johannes Kepler in the 17th century.[5]
It was C.M. Whish, a civil servant of East India Company, who brought to the attention of the western scholarship the existence of Tantrasamgraha through a paper published in 1835.[6] The other books mentioned by C.M. Whish in his paper were Yuktibhāṣā of Jyeshtadeva, Karanapaddhati of Puthumana Somayaji and Sadratnamala of Sankara Varman.
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Main article: Nilakantha Somayaji |
Nilakantha Somayaji, the author of Tantrasamgraha, was a Nambudiri belonging to the Gargya gotra and a resident of Trikkantiyur, near Tirur in central Kerala. The name of his Illam was Kelallur. He studied under Damodara, son of Paramesvara. The first and the last verses in Tantrasamgraha contain chronograms specifying the dates, in the form Kali days, of the commencement and of the completion of book. These work out to dates in 1500-01.[1]
A brief account of the contents of Tantrasamgraha is presented below.[4] A descriptive account of the contents is available in Bharatheeya Vijnana/Sastra Dhara.[7] Full details of the contents are available in an edition of Tantrasamgraha published in the Indian Journal of History of Science.[1]
"A remarkable synthesis of Indian spherical astronomical knowledge occurs in a passage in Tantrasamgraha."[8] In astronomy, the spherical triangle formed by the zenith, the celestial north pole and the Sun is called the astronomical triangle. Its sides and two of its angles are important astronomical quantities. The sides are 90° - φ where φ is the observer's terrestrial latitude, 90° - δ where δ is the Sun's declination and 90° - a where a is the Sun's altitude above the horizon. The important angles are the angle at the zenith which is the Sun's azimuth and the angle at the north pole which is the Sun's hour angle. The problem is to compute two of these elements when the other three elements are specified. There are precisely ten different possibilities and Tantrasamgraha contains discussions of all these possibilities with complete solutions one by one in one place.[9] "The spherical triangle is handled as systematically here as in any modern textbook."[8]
The terrestrial latitude of an observer's position is equal to the zenith distance of the Sun at noon on the equinoctial day. The effect of solar parallax on zenith distance was known to Indian astronomers right from Aryabhata. But it was Nilakantha Somayaji who first discussed the effect of solar parallax on the observer's latitude. Tantrasamgraha gives the magnitude of this correction and also a correction due to the finite size of the Sun.[10]
In his Aryabhatiyabhasya, a commentary on Aryabhata's Aryabhatiya, Nilakantha developed a computational system for a partially heliocentric planetary model in which Mercury, Venus, Mars, Jupiter and Saturn orbit the Sun, which in turn orbits the Earth, similar to the Tychonic system later proposed by Tycho Brahe in the late 16th century. Most astronomers of the Kerala school who followed him accepted this planetary model.[5][11]
A Conference to celebrate the 500th Anniversary of Tantrasangraha was organised by the Department of Theoretical Physics, University of Madras, in collaboration with the Inter-University Centre of the Indian Institute of Advanced Study, Shimla, during 11–13 March 2000, at Chennai.[12] The Conference turned out to be an important occasion for highlighting and reviewing the recent work on the achievements in Mathematics and Astronomy of the Kerala school and the new perspectives in History of Science, which are emerging from these studies. A compilation of the important papers presented at this Conference has also been published. [13]
The following is a brief description of the other works by Nilakantha Somayaji.[1]
