(b. Amber, Rajasthan, India, 1686; d. Jaipur, Rajasthan, 2 October 1743)
Savāī Jayasimha II, a Kachwāha Rajput, succeeded to the throne of Amber in 1699—not, of course, as a sovereign monarch but as a subordinate of the Mogul emperor. As maharaja he patronized a revival of Brahman culture, his most notable act in this regard being the performance of an aśvamedha, or “horse sacrifice,” in 1742. But his most fascinating effort was the attempt to restore Indian astronomy by introducing Islamic and European scientific works and instruments into the traditional astronomy.
In pursuit of his goal Jayasimha had many parts of the traditional Islamic course of study of mathematical astronomy translated into Sanskrit. Nasír al-Dín al-Túsí in 1255 had divided this course into three parts: the first contained Euclid’s Elements; the second, the “Middle Mathematics” or “Little Astronomy,” consisting of various works by Euclid, Theodosius, Autolycus, Aristarchus, Hypsicles, Archimedes, and Menelaus; and the third, Ptolemy’s Syntaxis Mathé-matiké The first and third parts of this course were translated by Jagannātha: the Euclid as the Rekhāganita shortly before 1727 and the Ptolemy as the Siddhāntasamrāt in 1732. In 1725 or 1730 Nayanasukhopādhyāya translated from Arabic into Sanskrit Theodosius’ Spherics (Ukara) (the second treatise in al-Tūsī’s “Middle Mathematics”), and it seems likely that Jayasimha was his patron. Jayasimha also patronized the preparation of a set of astronomical tables with instructions for their use in Persian, the Zīj-i-jadīdī Muhammad-Shāhī, which was probably written largely by Abū al-Khayr Khayr Allāh Khān and which Jayasimha dedicated to the Mogul emperor Muhammad Shāh in 1728. (The star catalog is dated 1725-1726; the preface was written after 1734.) This zīj contains tables for calendars, for oblique ascensions in the seven climes, and for planetary positions; it was intended to be an improvement on the zīj of Ulugh Beg and the Zīj-i Khāqāni of al-Kāshī.
Also imitative of Ulugh Beg was Jayasimha’s construction of five astronomical observatories—at Delhi, Jaipur (the capital city he founded in 1728), Ujjain, Benares, and Mathurā. The story related in the preface to his zīj that he had observations made at these observatories for seven years before publishing the zīj must be false—at least in the case of Jaipur, which was founded in the same year that the zīj was finished —and the observatories at Benares and Mathurā seem to have been built after 1734. Jayasimha did determine the obliquity of the ecliptic to be 23;28°(in 1729) and the latitude of Ujjain to be 23;10°, both of which values are very close to the truth; but what relationship there might be between his observations and the parameters employed in his zīj is not yet apparent. Jayasimha also used the Tabulae Astronomicae of Philippe de la Hire (published 1687-1702) and the Historia Coelestis Britannica of John Flamsteed (published 1712-1725), although his emissaries were not sent to Europe (Portugal) until 1728 or 1729, after publication of the zīj.
The instruments constructed for Jayasimha were of metal and stone. The metal instruments include astrolabes (yantrarāja), a graduated brass circle 17.5 feet in diameter, equatorial circles, and a declination circle (krāntivrttiyantra). The masonry instruments, which are the most spectacular remains of Jayasimha’s observatories, include huge equinoctial dials (samrātyantra), hemispherical dials (jayprakāśa), azimuth instruments (digamśayantra), meridian circles (daksinavrttiyantra), cylindrical dials (rāmayantra), fixed sextants (sastāmśayantra), “mixed instruments”(miśrayantra), and zodiacal dials (rāśiyantra)
Jayasimha wrote a work in Sanskrit, the Yantrarā-jaracanā, describing the astrolabe. His other work in Sanskrit is the Jayavinoda, a set of tables for computing tithis, naksatras, and yogas, written in 1735.
James Tod thus concludes his account of Jayasimha; “Three of his wives and several concubines ascended his funeral pyre, on which science expired with him.” In fact, his grand design to revitalize Indian astronomy failed. Although his zīj and other works and the translations of Jagannātha and Nayanasukhopā-dhyāya were copied, the observatories were abandoned. European advances in astronomy were ignored by Indian scientists until 1835, when the high school at Sihora in Mālwā, under the direction of Lancelot Wilkinson (the editor of many classical Sanskrit texts on astronomy and mathematics), began to teach and expound Western astronomy in Sanskrit.
(See essays on Indian science in Supplement.)
I. Original Works. The Yantrarājaracanā was published in Pandit (Jaipur), 1, no. 1 (1924), together with a note by A. ff. Garrett; and again with Kedāranātha’s own commentary, Yantrarājaprabhā and the Yantrarājaprabhā of Śrīnātha by Kedāranātha, Rajasthan Oriental series no.5 (Jaipur, 1953). An incomplete version of Jayasimha’s Jayavinoda is described in D. Pingree, “Sanskrit Astronomical Tables in the United States,” in Transactions of the American Philosophical Society, n.s. 58 , no. 3 (1668), 66b-67a.
II. Secondary Literature. The best treatment of Jayasimha’s life remains James Tod, Annals and Antiquities of Rajasthan, 3 vols. (Oxford, 1920), vol. 3, pp. 1341-1356. Among numerous articles dealing with various aspects of his life are D . C. Sircar, “Sewai Jaysingh of Amber, A.D. 1699-1743,” in Indian Culture, 3 (1936-1937), 376-379; P. K. Gode,“The Aśvamedha Performed by Sevai Jayasing of Amber (1699-1744 A.D.),” in Poona Orientalist,2 (1937), 166-180; V.S. Bhatnagar, “The Date of Aśvamedha Performed by Sawai Jai Singh of Jaipur,” in Journal of the Bihar Research Society,46 (1960), 151-154; and P. D. Pathak, “A Further Evidence on Sawai Jai Singh and the New City of Jaipur Founded by Him With Reference to Buddhi-vilāsa—a Contemporary Jain Work,” in Journal of the Oriental Institute, Baroda1,13 (1963-1964), 281-284.
An article on Jayasimha as an astronomer is in Ś. B. Diksita, Bhāratīya Jyotihśāstra (Poona, 1896; repr. Poona, 1931), pp. 292-295. A bibliography of the unpuplished Zīj-ī jadid-ī Muhammad-Shahi is in C. A. Storey, Persian Literature, 11, pt. 1 (London, 1958), 93-94;W. Hunter’s articles (see below) is most informative regarding the contents of the Zīj. But the observatories have received the most attention; on them see R. Barker,“An Account of the Brahmin’s Observatories have received the most attention; on them see R. Barkar,“in Philosophical Transactions of the Royal society,67 (1777), pt. 2, 598-607; J. L. Williams,“Further Particulars Respecting the Observatory at Benares,’ in philosophical Transactions of the Royal Society,88 (1793), pt. 1, 45-49; W. Hunter,“Some Account of the Astronomical Labours of Jayasinha, Rajah of Ambhere or Jaynagar’ in Asiatic Researches,5 (1799), 177-211, 424; A. ff. Garrett and C. Guleri, The Jaipur Observatory and Its Builder (Allahabad, 1902); S. Noti, Land und Volk des Koniglichen Astronomer Dschaisingh 11 Maharadscha von Dschaipur (Berlin, 1911);and A.p. Stone, “Astronomical Instruments at Calcutta, Delhi and Jaipur,’ in Archives internationales d’histoire des sciences, 42 (1958), 159-162 The standard work is G. R. Kaye, The Astronomical Observatories of Jai Singh, Memoirs of the Archaeological Survey of India, Imperial Series 40 (Calcutta, 1918);a short version of this is Kaye, A Guide to the Old Observatories at Delhi;Jaipur;Ujjain; Benares (Calcutta, 1920).