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Historical Indian astronomy developed as a discipline of Vedanga or one of the "auxiliary disciplines" associated with the study of the Vedas, dating 1500 BCE or older. The oldest known text is the Vedanga Jyotisha, dated to 1400–1200 BCE (with the extant form possibly from 700–600 BCE).

As with other traditions, the original application of astronomy was thus religious. Indian astronomy was influenced by Greek astronomy beginning in the 4th century BCE and through the early centuries of the Common Era, for example by the Yavanajataka and the Romaka Siddhanta, a Sanskrit translation of a Greek text disseminated from the 2nd century.

Indian astronomy flowered in the 6th century, with Aryabhata, whose Aryabhatiya represented the pinnacle of astronomical knowledge at the time. Later the Indian astronomy significantly influenced medieval Muslim astronomy, Chinese astronomy, European astronomy, and others. Other astronomers of the classical era who further elaborated on Aryabhata's work include Brahmagupta, Varahamihira and Lalla.

An identifiable native Indian astronomical tradition remained active throughout the medieval period and into the 16th or 17th century, especially within the Kerala school of astronomy and mathematics.

History

Some cosmological concepts are present in the Vedas, as are notions of the movement of heavenly bodies and the course of the year. As in other traditions, there is a close association of astronomy and religion during the early history of the science, astronomical observation being necessitated by spacial and temporal requirements of correct performance of religious ritual. Thus, the Shulba Sutras, texts dedicated to altar construction, discusses advanced mathematics and basic astronomy. Jyotiṣa Vedānga as the science of observing the heavens in order to correctly perform Vedic sacrifice arises after the end of the Vedic period, during ca. the 6th to 4th centuries BCE.

Greek astronomical ideas began to enter India in the 4th century BCE following the conquests of Alexander the Great. By the early centuries of the Common Era, Indo-Greek influence on the Vedanga tradition is visible, with texts such as the Yavanajataka and Romaka Siddhanta. Later astronomers mention the existence of various siddhantas during this period, among them a text known as the Surya Siddhanta. But these weren't fixed texts but rather an oral tradition of knowledge, and their content is not extant. The text today known as Surya Siddhanta dates to the Gupta period and was received by Aryabhata.

The classical era of Indian astronomy begins in the late Gupta era, in the 5th to 6th centuries. The Pañcasiddhāntikā (Varahimira, 505 CE) approximates the method for determination of the meridian direction from any three positions of the shadow using Gnomon. By the time of Aryabhata I the motion of planets was treated to be elliptical rather than circular. Other topics included definitions of different units of time, eccentric models of planetary motion, epicyclic models of planetary motion, and planetary longitude corrections for various terrestrial locations.

Calendars

The divisions of the year were on the basis of religious rites and seasons (Rtu). The duration from mid March—Mid May was taken to be spring (vasanta), mid May—mid July: summer ("grishma"), mid July—mid September: rains (varsha), mid September—mid November: autumn, mid November—mid January: winter, mid January—mid March: dew (śiśira).

In the Vedānga Jyotiṣa, the year begins with the winter solstice. Hindu calendars have several eras:

• The Hindu calendar, counting from the start of the Kali Yuga, has its epoch on 18 February 3102 BCE Julian (23 January 3102 BCE Gregorian).
• The Vikrama Samvat calendar, introduced about the 12th century, counts from 56–57 BCE.
• The "Saka Era", used in some Hindu calendars and in the Indian national calendar, has its epoch near the vernal equinox of year 78.
• The Saptarshi calendar traditionally has its epoch at 3076 BCE.

J.A.B. van Buitenen (2008) reports on the calendars in India:

The oldest system, in many respects the basis of the classical one, is known from texts of about 1000 BCE. It divides an approximate solar year of 360 days into 12 lunar months of 27 (according to the early Vedic text Taittirīya Saṃhitā 4.4.10.1–3) or 28 (according to the Atharvaveda, the fourth of the Vedas, 19.7.1.) days. The resulting discrepancy was resolved by the intercalation of a leap month every 60 months. Time was reckoned by the position marked off in constellations on the ecliptic in which the Moon rises daily in the course of one lunation (the period from New Moon to New Moon) and the Sun rises monthly in the course of one year. These constellations (nakṣatra) each measure an arc of 13° 20′ of the ecliptic circle. The positions of the Moon were directly observable, and those of the Sun inferred from the Moon's position at Full Moon, when the Sun is on the opposite side of the Moon. The position of the Sun at midnight was calculated from the nakṣatra that culminated on the meridian at that time, the Sun then being in opposition to that nakṣatra.

Astronomers

Instruments used

Among the devices used for astronomy was Gnomon, known as Sanku, in which the shadow of a vertical rod is applied on a horizontal plane in order to ascertain the cardinal directions, the latitude of the point of observation, and the time of observation. This device finds mention in the works of Varāhamihira, Āryabhata, Bhāskara, Brahmagupta, among others. The Cross-staff, known as Yasti-yantra, was used by the time of Bhaskara II (1114–1185 CE). This device could vary from a simple stick to V-shaped staffs designed specifically for determining angles with the help of a calibrated scale. The clepsydra (Ghatī -yantra) was used in India for astronomical purposes until recent times. Ōhashi (2008) notes that: "Several astronomers also described water-driven instruments such as the model of fighting sheep."

The armillary sphere was used for observation in India since early times, and finds mention in the works of Āryabhata (476 CE). The Goladīpikā—a detailed treatise dealing with globes and the armillary sphere was composed between 1380–1460 CE by Parameśvara. On the subject of the usage of the armillary sphere in India, Ōhashi (2008) writes: "The Indian armillary sphere (gola-yantra) was based on equatorial coordinates, unlike the Greek armillary sphere, which was based on ecliptical coordinates, although the Indian armillary sphere also had an ecliptical hoop. Probably, the celestial coordinates of the junction stars of the lunar mansions were determined by the armillary sphere since the seventh century or so. There was also a celestial globe rotated by flowing water."

An instrument invented by the mathematician and astronomer Bhaskara II (1114–1185 CE) consisted of a rectangular board with a pin and an index arm. This device—called the Phalaka-yantra—was used to determine time from the sun's altitude. The Kapālayantra was an equatorial sundial instrument used to determine the sun's azimuth. Kartarī-yantra combined two semicircular board instruments to give rise to a 'scissors instrument'. Introduced from the Islamic world and first finding mention in the works of Mahendra Sūri—the court astronomer of Firuz Shah Tughluq (1309–1388 CE)—the astrolabe was further mentioned by Padmanābha (1423 CE) and Rāmacandra (1428 CE) as its use grew in India.

Invented by Padmanābha, a nocturnal polar rotation instrument consisted of a rectangular board with a slit and a set of pointers with concentric graduated circles. Time and other astronomical quantities could be calculated by adjusting the slit to the directions of α and β Ursa Minor. Ōhashi (2008) further explains that: "Its backside was made as a quadrant with a plumb and an index arm. Thirty parallel lines were drawn inside the quadrant, and trigonometrical calculations were done graphically. After determining the sun’s altitude with the help of the plumb, time was calculated graphically with the help of the index arm."

Ōhashi (2008) reports on the observatories constructed by Jai Singh II of Amber:

The Mahārāja of Jaipur, Sawai Jai Singh (1688–1743 CE), constructed five astronomical observatories at the beginning of the eighteenth century. The observatory in Mathura is not extant, but those in Delhi, Jaipur, Ujjain, and Banaras are. There are several huge instruments based on Hindu and Islamic astronomy. For example, the samrāt.-yantra (emperor instrument) is a huge sundial which consists of a triangular gnomon wall and a pair of quadrants toward the east and west of the gnomon wall. Time has been graduated on the quadrants.

The seamless celestial globe invented in Mughal India, specifically Lahore and Kashmir, is considered to be one of the most impressive astronomical instruments and remarkable feats in metallurgy and engineering. All globes before and after this were seamed, and in the 20th century, it was believed by metallurgists to be technically impossible to create a metal globe without any seams, even with modern technology. It was in the 1980s, however, that Emilie Savage-Smith discovered several celestial globes without any seams in Lahore and Kashmir. The earliest was invented in Kashmir by Ali Kashmiri ibn Luqman in 998 AH (1589–90 CE) during Akbar the Great's reign; another was produced in 1070 AH (1659–60 CE) by Muhammad Salih Tahtawi with Arabic and Sanskrit inscriptions; and the last was produced in Lahore by a Hindu metallurgist Lala Balhumal Lahuri in 1842 during Jagatjit Singh Bahadur's reign. 21 such globes were produced, and these remain the only examples of seamless metal globes. These Mughal metallurgists developed the method of lost-wax casting in order to produce these globes.

Global discourse

Indian, Babylonian and Greek astronomy

The earliest known Indian astronomical work (though it is restricted to calendrical discussions) is the Vedanga Jyotisha of Lagadha, which has not yet been conclusively datedost Jyotisha Vedanga, all Indian astronomical texts are dated to the sixth century CE or later with a high degree of certainty. There is substantial similarity between these and pre-Ptolomaic Greek astronomy. Pingree detects the Greek origin of Indian astronomy in these similarities. This has been contested by Van Der Waerden, who maintains the originality and independent development of Indian astronomy.

Indian and Chinese astronomy

Indian astronomy reached China with the expansion of Buddhism during the Later Han (25–220 CE). Further translation of Indian works on astronomy was completed in China by the Three Kingdoms era (220–265 CE). However, the most detailed incorporation of Indian astronomy occurred only during the Tang Dynasty (618–907) when a number of Chinese scholars—such as Yi Xing— were versed both in Indian and Chinese astronomy. A system of Indian astronomy was recorded in China as Jiuzhi-li (718 CE), the author of which was an Indian by the name of Qutan Xida—a translation of Devanagari Gotama Siddha—the director of the Tang dynasty's national astronomical observatory.

Fragments of texts during this period indicate that Arabs adopted the sine function (inherited from Indian mathematics) instead of the chords of arc used in Hellenistic mathematics. Another Indian influence was an approximate formula used for timekeeping by Muslim astronomers. Through Islamic astronomy, Indian astronomy had an influence on European astronomy via Arabic translations. During the Latin translations of the 12th century, Muhammad al-Fazari's Great Sindhind, which was based on the Surya Siddhanta and the works of Brahmagupta, was translated into Latin in 1126 and was influential at the time.

Indian and Islamic astronomy

In the 17th century, the Mughal Empire saw a synthesis between Islamic and Hindu astronomy, where Islamic observational instruments were combined with Hindu computational techniques. While there appears to have been little concern for planetary theory, Muslim and Hindu astronomers in India continued to make advances in observational astronomy and produced nearly a hundred Zij treatises. Humayun built a personal observatory near Delhi, while Jahangir and Shah Jahan were also intending to build observatories but were unable to do so. After the decline of the Mughal Empire, it was a Hindu king, Jai Singh II of Amber, who attempted to revive both the Islamic and Hindu traditions of astronomy which were stagnating in his time. In the early 18th century, he built several large observatories called Yantra Mandirs in order to rival Ulugh Beg's Samarkand observatory and in order to improve on the earlier Hindu computations in the Siddhantas and Islamic observations in Zij-i-Sultani. The instruments he used were influenced by Islamic astronomy, while the computational techniques were derived from Hindu astronomy.

Indian astronomy and Europe

Some scholars have suggested that knowledge of the results of the Kerala school of astronomy and mathematics may have been transmitted to Europe through the trade route from Kerala by traders and Jesuit missionaries. Kerala was in continuous contact with China and Arabia, and Europe. The existence of circumstantial evidence such as communication routes and a suitable chronology certainly make such a transmission a possibility. However, there is no direct evidence by way of relevant manuscripts that such a transmission took place.

In the early 18th century, Jai Singh II of Amber invited European Jesuit astronomers to one of his Yantra Mandir observatories, who had bought back the astronomical tables compiled by Philippe de La Hire in 1702. After examining La Hire's work, Jai Singh concluded that the observational techniques and instruments used in European astronomy were inferior to those used in India at the time - it is uncertain whether he was aware of the Copernican Revolution via the Jesuits. He did, however, employ the use of telescopes. In his Zij-i Muhammad Shahi, he states: "telescopes were constructed in my kingdom and using them a number of observations were carried out."

Following the arrival of the British East India Company in the 18th century, the Hindu and Islamic traditions were slowly displaced by European astronomy, though there were attempts at harmonising these traditions. The Indian scholar Mir Muhammad Hussain had travelled to England in 1774 to study Western science and, on his return to India in 1777, he wrote a Persian treatise on astronomy. He wrote about the heliocentric model, and argued that there exists an infinite number of universes (awalim), each with their own planets and stars, and that this demonstrates the omnipotence of God, who is not confined to a single universe. Hussain's idea of a universe resembles the modern concept of a galaxy, thus his view corresponds to the modern view that the universe consists of billions of galaxies, each one consisting of billions of stars. The last known Zij treatise was the Zij-i Bahadurkhani, written in 1838 by the Indian astronomer Ghulam Hussain Jaunpuri (1760–1862) and printed in 1855, dedicated to Bahadur Khan. The treatise incorporated the heliocentric system into the Zij tradition.

See also

• History of astronomy
• Chinese astronomy
• Islamic astronomy
• Hindu calendar
• Hindu cosmology
• Hindu chronology
• List of numbers in Hindu scriptures

Further reading

• Brennand, W. (1896), Hindu Astronomy, Chas.Straker & Sons,London
• Maunder, E. Walter (1899), The Indian Eclipse 1898, Hazell Watson and Viney Ltd., London

Notes

1. ^ Sarma (2008), Astronomy in India
2. By Colin Spencer, The Heretic's Feast: A History of Vegetarianism - Page 69
3. Subbarayappa, B. V. (14 September 1989). "Indian astronomy: An historical perspective". In Biswas, S. K.; Mallik, D. C. V.; Vishveshwara, C. V. (ed.). Cosmic Perspectives. Cambridge University Press. pp. 25–40. ISBN 978-0-521-34354-1.{{cite book}}: CS1 maint: multiple names: editors list (link)
4. ^ Highlights of Astronomy, Volume 11B: As presented at the XXIIIrd General Assembly of the IAU, 1997. Johannes Andersen Springer, 31 January 1999 – Science – 616 pages. page 721
5. ^ Babylon to Voyager and Beyond: A History of Planetary Astronomy. David Leverington. Cambridge University Press, 29 May 2003 – Science – 568 pages. page 41
6. ^ The History and Practice of Ancient Astronomy. James Evans. Oxford University Press, 1 October 1998 – History – 496 pages. Page 393
7. ^ Foreign Impact on Indian Life and Culture (c. 326 B.C. to C. 300 A.D.). Satyendra Nath Naskar. Abhinav Publications, 1 January 1996 – History – 253 pages. Pages 56–57
8. "Star Maps: History, Artistry, and Cartography", p. 17, by Nick Kanas, 2012
9. ^ Abraham (2008)
10. Ōhashi (1993)
11. ^ Hayashi (2008), Aryabhata I
12. ^ J.A.B. van Buitenen (2008)
13. Bryant (2001), 253
14. See A. Cunningham (1883), A Book of Indian Eras.
15. ^ Subbaarayappa (1989)
16. ^ Tripathi (2008)
17. ^ Hayashi (2008), Brahmagupta
18. Brahmagupta, Brahmasphutasiddhanta (628) (cf. al-Biruni (1030), Indica)
19. ^ Varāhamihira. Encyclopædia Britannica (2008)
20. ^ Hayashi (2008), Bhaskara I
21. ^ Sarma (2008), Lalla
22. Hayashi (2008), Bhaskara II
23. Hayashi (2008), Shripati
24. ^ Ōhashi (1997)
25. ^ Joseph, 408
26. Ramasubramanian etc. (1994)
27. ^ Sarma (2008), Acyuta Pisarati
28. ^ Ōhashi (2008), Astronomical Instruments in India
29. ^ Sarma (2008), Armillary Spheres in India
30. Savage-Smith (1985)
31. Pingree, David (1976). "The Recovery of early Greek Astronomy from India". The Journal of History of Astronomy. vii. Science History Publications Ltd.: 109–123. {{cite journal}}: Unknown parameter |yul= ignored (help)
32. B. L. Van Der Waerden (1980). "Two Treatises on Indian Astronomy". The Journal of History of Astronomy. xi. Science History Publications Ltd.: 50–62.
33. ^ See Ōhashi (2008) in Astronomy: Indian Astronomy in China.
34. Dallal, 162
35. King, 240
36. Joseph, 306
37. Sharma (1995), 8–9
38. Baber, 82–89
39. ^ Almeida etc. (2001)
40. Raju (2001)
41. Baber, 89–90
42. S. M. Razaullah Ansari (2002), History of oriental astronomy: proceedings of the joint discussion-17 at the 23rd General Assembly of the International Astronomical Union, organised by the Commission 41 (History of Astronomy), held in Kyoto, August 25–26, 1997, Springer, p. 141, ISBN 1-4020-0657-8
43. S. M. Razaullah Ansari (2002), History of oriental astronomy: proceedings of the joint discussion-17 at the 23rd General Assembly of the International Astronomical Union, organised by the Commission 41 (History of Astronomy), held in Kyoto, August 25–26, 1997, Springer, pp. 133–4, ISBN 1-4020-0657-8
44. S. M. Razaullah Ansari (2002), History of oriental astronomy: proceedings of the joint discussion-17 at the 23rd General Assembly of the International Astronomical Union, organised by the Commission 41 (History of Astronomy), held in Kyoto, August 25–26, 1997, Springer, p. 138, ISBN 1-4020-0657-8

References

• Use dmy dates from March 2013
• Hindu astronomy
• Ancient astronomy
• History of astronomy
• History of astrology
• Astronomy in India