Everything about Indian Astronomy totally explained
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
While the
Vedanga Jyotisha of Ladaga documents the state of Indian astronomy in the
Maurya period, astronomy of the classical
Gupta period, the centuries following
Indo-Greek contact, is documented in treatises known as
Siddhantas (which means "established conclusions" ).
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 :
- 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 couldn't locate any extant version), (5)Nārada-siddhānta.
- By ancient sages : (6)Garga-siddhānta, (7)Vyāsa-siddhānta, (8)Parāśara-siddhānta, (9)Pauliśa-siddhānta, (10)Pulastya-siddhānta, (11)-siddhānta.
- Ancient authors : (12)Laghu Arya-siddhānta, (13)-Arya-siddhānta, (14)Varāha-siddhānta, (15)Brahma-siddhānta (of Brahmagupta), (16)Romaka-siddhānta.
- Dated authors : (17)Bhoja-siddhānta, (18)Siddhānta-śiromani, (19)Siddhānta-sundara, (20)Graha-lāghava, (21)Siddhānta-tattva-viveka, (22)Siddhānta-sārvabhauma.
Coordinate system
In Hindu Astronomy, the
vernal equinox (the
First Point of Aries) is often calculated at 23°From 0°
Aries (1950 CE), for example about 7°
Pisces. The constellation that marks this vernal
equinox is the Uttarabhadra.
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
There are a large number of computational planetary models presently employed by almanac makers in India. Many Indian almanacs are now prepared on the basis of modern astronomy, including the Rashtriya Panchanga published by government, which no pandit buys. Surya Siddhānta, two Ārya Siddhāntas of two Āryabhattas and Brahma Siddhānta are major ancient theoretical models which form the basis of most of traditional almanacs. Of these
Surya Siddhanta ("Saura") is the most important, which Vārāha Mihira had declared in ca. 550 AD to be the "most accurate" . It is interesting to note that Vārāha Mihira didn't include
Aryabhatiya among the five major siddhantas dealt by him, although Āryabhatiya had been written just half a century before Pañcasiddhāntika.
Āryabhatan model
Aryabhata (
476–
550), in his magnum opus
Aryabhatiya, propounded a computational system based on a planetary model in which the Earth was taken to be
rotating on its axis and the periods of the planets were given with respect to the Sun. Some have interpreted this to be a
heliocentric model,
but this view has been disputed by others.
He recognized that the light from the Moon and the planets was reflected from the Sun and accurately calculated many astronomical constants, such as the periods of the planets, times of the
solar and
lunar eclipses, and the instantaneous motion of the Moon (expressed as a
differential equation). The first major astronomer to attack the
Aryabhatiya was
Varahamihira.
Brahmagupta was the greatest critic of Aryabhatiya; he devoted an entire chapter 'Tantra Parikshā' in his treatise
Brāhm-Sphuta-Siddhānta to criticizng the
Aryabhatiya in the harshest of terms.
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 isn't 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
In 1500,
Nilakanthan Somayaji (1444-1544) of the
Kerala school of astronomy and mathematics, in his
Tantrasangraha, revised
Aryabhata's model for the planets
Mercury and
Venus. His equation of the
centre for these planets remained the most accurate until the time of
Johannes Kepler in the 17th century.
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. The Yavanajataka ("Sayings 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.
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....." The Garga Samhita also says: "The Yavanas are barbarians, yet the science of astronomy originated with them and for this they must be reverenced like gods."
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, 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
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.
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. such as communication routes and a suitable chronology certainly make such a transmission a possibility. However, there's 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 didn't 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: freezeFurther Information
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