Indian astronomy refers to the study of astronomy in the Indian subcontinent, as documented in literature spanning the Maurya (Vedanga Jyotisha, ca. 3rd century BCE) to the Mughal (such as the 16th century Kerala school) periods.

The astronomy and the astrology of ancient India (Jyotisha) is mainly based on a sidereal system of calculations. A tropical system has also been used in a few cases. For example, a tropical determination of the Uttarayana (Uttarāyana उत्तरायन) is found in the Mahabharata, and also in the Vedanga Jyotisha of Lagadha, but not in subsequent systems, which have been sidereal.

The first named authors writing treatises on astronomy emerge from the 5th century CE, the date when the classical period of Indian astronomy can be said to begin. Besides the theories of Aryabhata in the Aryabhatiya and the lost Arya-siddhānta, we find the Pancha-Siddhāntika of Varahamihira. From this time on, we find a predominance of geocentric models, and possibly heliocentric models, in Indian astronomy, in contrast to the "Merucentric" astronomy of Puranic, Jaina and Buddhist traditions whose actual mathematics has been largely lost and only fabulous accounts remain.

Literature

Varahamihira in his Pancha-Siddhantika contrasts five fo these: The Surya Siddhanta besides the Paitamaha Siddhantas (which is more similar to the "classical" Vedanga Jyotisha), the Paulisha and Romaka Siddhantas (directly based on Hellenistic astronomy) and the Vasishta Siddhanta.

The work referred to by the title Surya Siddhanta has been repeatedly recast. There may have been an early work under that title dating back to the Buddhist Age of India (3rd century BC). The work as preserved and edited by Burgess (1858) dates to the Middle Ages.

Whitney classifies these ancient siddhāntas into four categories : "a revelation", "attributed to ancient and renowned sage", "works of actual authors", and "later texts of known date and authorship" . Only a few of these ancient siddhāntas can be adequately reconstructed and some of them might have been vitiated by later interpolators . Whitney's list of these siddhāntas are as follows according to four categories of Whitney :

1. Revelations : (1)Brahma-siddhānta (a part of ; now lost), (2)Surya-siddhānta, (3)Soma-siddhānta(Bentley said it followed the system of Surya Siddhānta), (4)-siddhānta (Whitney could not locate any extant version), (5)Nārada-siddhānta.
2. By ancient sages : (6)Garga-siddhānta, (7)Vyāsa-siddhānta, (8)Parāśara-siddhānta, (9)Pauliśa-siddhānta, (10)Pulastya-siddhānta, (11)-siddhānta.
3. Ancient authors : (12)Laghu Arya-siddhānta, (13)-Arya-siddhānta, (14)Varāha-siddhānta, (15)Brahma-siddhānta (of Brahmagupta), (16)Romaka-siddhānta.
4. Dated authors : (17)Bhoja-siddhānta, (18)Siddhānta-śiromani, (19)Siddhānta-sundara, (20)Graha-lāghava, (21)Siddhānta-tattva-viveka, (22)Siddhānta-sārvabhauma.

Coordinate system

In the time of the Puranas, the vernal equinox was marked by the Ashwini constellation (beginning of Aries), which gives a date of about 300-500 CE. The Vishnu Purana (2.8.63) states that the equinoxes occur when the Sun enters Aries] and Libra, and that when the sun enters Capricorn, his northern course (from winter to summer solstice) commences, and the southern course when he enters Cancer.The Brahmanas place the Equinox in Krittika (Pleidas) and the Rig Veda in Mrigasira (Orion). These would indicate a time of around 1900 BCE and 4000 BCE, respectively.

In the Surya Siddhanta, the rate of precession is set at 54" (it actually is 50.3"), which is much more accurate than the number calculated by the Greeks.

The Hindus use a system of 27 or 28 Nakshatras (lunar constellations) to calculate a month. Each month can be divided into 30 lunar tithis (days). There are usually 360 or 366 days in a year.

It has been argued that Nilakantha Somayaji's (1444-1550) work shows a better equation of the center for Mercury and Venus "than was available either in the earlier Indian works or in the Islamic or European traditions of astronomy till the work of Kepler, which was to come more than a hundred years later.

Computational planetary models

Āryabhatan model

Bhaskara II (1114–1185) expanded on early models in his astronomical treatise Siddhanta-Shiromani, where he mentioned the law of gravity, discovered that the planets don't orbit at a uniform velocity, and calculated many astronomical constants based on this model, such as the solar and lunar eclipses, and the velocities and instantaneous motions of the planets.

Arabic translations of Aryabhata's Aryabhatiya, known as Jije Al Arzbahar by al-Khwarizmi, were available from the 8th century but is not available now, while Latin translations were available from the 13th century, before Copernicus had written De revolutionibus orbium coelestium. In 1030, al-Biruni had also discussed the theories of Aryabhata, Brahmagupta and Varahamihira in his Ta'rikh al-Hind (Indica in Latin; Chronicles of India in English), often quoting Brahmagupta's Brahmasiddhānta for authoritative statements. Regarding whether the earth was at rest or revolving, the latter being the view of Aryabhata, he wrote:

Nilakanthan model

Nilakanthan Somayaji, in his Aryabhatiyabhasya, a commentary on Aryabhata's Aryabhatiya, developed his own 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. Nilakantha's system, however, was mathematically more effient than the Tychonic system, due to correctly taking into account the equation of the centre and latitudinal motion of Mercury and Venus. Most astronomers of the Kerala school of astronomy and mathematics who followed him accepted his planetary model.

Calendars

In the Vedanga Jyotisa, 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 BC Julian (23 January 3102 BC Gregorian).
• The Vikrama Samvat calendar, introduced about the 12th century, counts from 56-57 BC,.
• 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.

Interactions with foreign traditions

Hellenistic astronomy

Hellenistic astronomy is known to have been practiced near India in the Greco-Bactrian city of Ai-Khanoum from the 3rd century BCE. Various sun-dials, including an equatorial sundial adjusted to the latitude of Ujjain have been found in archaeological excavations there. Numerous interactions with the Mauryan Empire, and the later expansion of the Indo-Greeks into India suggest that some transmission may have happened during that period.

Several Greco-Roman astrological treatises are also known to have been imported into India during the first few centuries of our era. Some say that the Yavanajataka ("astronomy of the Greeks") was translated from Greek to Sanskrit by Yavanesvara during the 2nd century CE, under the patronage of the Western Satrap Saka king [[Rudradaman I]but no original Greek book is available to substantiate this view. Actually the original text was the Sanskrit prose text composed by Mayasura, who was called Yavaneshvara. Sphuridhvaja during the time of the Satrapa king Rudradamana wrote it in Sanskrit in the verse form and called versified version as the Yavanajataka..

Later in the 6th century, the Romaka Siddhanta ("Doctrine of the Romans"), and the Paulisa Siddhanta ("Doctrine of Paul") were considered as two of the five main astrological treatises, which were compiled by Varahamihira in his Pañca-siddhāntikā ("Five Treatises"). Varahamihira wrote in the Brihat-Samhita: "The Greeks, though impure, must be honored since they were trained in sciences and therein, excelled others.....

Chinese astronomy

The astronomical table of sines by the Indian mathematician and astronomer, Aryabhata, were translated into the Chinese mathematical book of the Treatise on Astrology of the Kaiyuan Era (Kaiyuan Zhanjing), compiled in 718 AD during the Tang Dynasty.

The Kaiyuan Zhanjing was compiled by Gautama Siddha, an astronomer and mathematician born in Chang'an, and whose family was originally from India. He was also notable for his translation of the Navagraha calendar into Chinese.

Islamic astronomy

Early Islamic astronomy was greatly influenced by Indian astronomy, particularly the Surya Siddhanta and the works of Aryabhata and Brahmagupta, which were translated from Sanskrit into Arabic. These works were compiled as the Zij al-Sindhind, based on the Surya Siddhanta and the works of Brahmagupta, which were translated by Muhammad al-Fazari and Yaqūb ibn Tāriq in 777. Sources indicate that the text was translated after an Indian astronomer visited the court of Caliph Al-Mansur in 770.

Fragments of texts during this period indicate that Arabs adopted the sine function (inherited from Indian trigonometry) instead of the chords of arc used in Hellenistic mathematics. Another Indian influence was an approximate formula used for timekeeping by Muslim astronomers.

Nearly a thousand years later in the 17th century, the Mughal Empire saw a synthesis between Islamic and Indian 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, however, 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 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.

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 seam, 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.

European astronomy

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.

Later in the early 18th century, Jai Singh II of Amber invited European Jesuit astronomers to his observatory, 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, but it appears Indian astronomers were not concerned with planetary theory, hence the theoretical advances in Europe did not interest them at the time.

Terminology

Seasons

• madhu, madhava in vasanta: spring
• sukra, suci in grisma: summer
• nabha, nabhasya in varsa: rains
• isa, urja in sarada: autumn
• saha, sahasya in hemanta: winter
• tapa, tapasya in sisira: freeze

See also

• History of astronomy
• Aryabhata
• Aryabhatiya
• Surya Siddhanta
• Yuga
• Indian mathematics
• Science and technology in ancient India
• Jyotish (Vedic astrology)
• Archaeoastronomy and Vedic chronology
• Hindu calendar
• Hindu units of measurement
• Hindu cosmology
• Chinese astronomy
• Islamic astronomy

Notes

References

• Ebenezer Burgess. "Surya-Siddhanta, Text with English Translation and Notes",Edited by S.Jain,Oriental Book Centre,Delhi,2005, ISBN 81-8315-017-9, pp.552 plus editorial 52 pages.
• Ebenezer Burgess. "Translation of the Surya-Siddhanta, a text-book of Hindu Astronomy", Journal of the American Oriental Society 6 (1860): 141–498.
• Surya Siddhānta,with Hindi commentary by Dr Rāmchandra Pāndey (Head of Department of , BHU University),Chowkhambā,Vārānasi.

• • G.Thibaut and Sudhakar Dwivedi."Panchasiddhantika",Chowkhambha,Varanasi, India,1888,reprint 1997
  • Gunākar Mule,Shruti-Smriti Paramparā and Ganitajna-Jyotishi Aryabhatta, published in Itihāsa,vol.3, Jan-Dec 1994, Research magagine of 'Indian Historical Research Council',35 Firoze Shah Road, New Delhi.
  • Bhāskarāchārya, Siddhāntaśiromani, published by Chowkhambā Sanskrit Sansthāna, Vārānasi, 3rd reprint 1999.
  • Burgess, Ebenezer (tr.) The Surya Siddhanta. Delhi: Motilal Banarsidass, 1989 (1860)
  • Kuppanna Sastry, T.S., Vedanga Jyotisha of Lagadha. Indian National Science Academy, Delhi 1985.
  • Vidyalankara, V. Satapatha Brahmanastha Agnicayana Samiksa. Bahalgarh, 1985.
  • Rāmniwās Rāi, Āryabhatiya,with Hindi commentary, published by Indian National Science Academy, Bahādurshāh Zafar Mārg, New Delhi,1976 (published on the occasion of 1500th birth anniversary of Āryabhata).Secondary literature
  • J.M. Roberts, The Hutchinson History of the World, BI Publications, 54 Janpath, New Delhi-1 (In association with Hutchinson Publishing Group of 3 Fitzroy Square, London W.1).
  • Billard, R. L'Astronomie Indienne. Ecole Francaise d'Extreme Orient, Paris, 1971.
  • Duke, Dennis. 2005. "The Equant in India: The Mathematical Basis of Ancient Indian Planetary Models." Archive for History of Exact Sciences 59: 563–576
  • Filliozat, Jean. 1969. "Notes on Ancient Iranian and Indian Astronomy." Journal of the K.R. Cama Oriental Research Institute 42:100-135.
  • Sri Yukteswar Giri. The holy science. Los Angeles, Ca: Self-Realization Fellowship, 1984.
  • Joseph, George G. (2000). The Crest of the Peacock: Non-European Roots of Mathematics, 2nd edition. Penguin Books, London. ISBN 0691006598
  • Kak, Subhash C. (2000). 'Birth and Early Development of Indian Astronomy'. In Selin, Helaine (2000). Astronomy Across Cultures: The History of Non-Western Astronomy (303-340). Kluwer, Boston. ISBN 0-7923-6363-9.
  • Kramrisch, S. The Presence of Siva. Princeton University Press, Princeton 1981.
  • Pingree, David (1978). "History of Mathematical astronomy in India." Dictionary of Scientific Biography, vol. 15, pp. 533–633, New York: Charles Scribner's Sons.
  • Pingree, David (1996). "Astronomy in India." in Christopher Walker, ed., Astronomy before the telescope, pp. 123-142. London: British Museum Press. ISBN 0-7141-1746-3.
  • Sen, S.N., and K.S. Shukla, eds. 1985. History of Astronomy in India. New Delhi: Indian National Science Academy.
  • Thurston, Hugh (1994). Early Astronomy. Springer-Verlag, New York. ISBN 0-387-94107-X
  • Nemichandra (Śāstri) Jain, Bhāratiya , published by Bhāratiya Jñānpith, New Delhi, 31rst reprint 2000, ISBN 81-263-0003-5.

  External links

  • Online course material for InSIGHT, a workshop on traditional Indian sciences for school children conducted by the Computer Science department of Anna University, Chennai, India.
  • http://www.galileotelescope.com
  • http://www.bharatvani.org/books/ait/ch22.htm
  • http://www.sanskrit.org/Astronomy/Astronomy%20Index.htm
  • http://www.jqjacobs.net/astro/aryabhata.html
  • Bjorn Merker, Rig Veda Riddles In Nomad Perspective, Mongolian Studies, Journal of the Mongolian Society XI, 1988.