Vedic astronomy (or pre siddhanthic astronomy)
Part I: References to Astronomy/ astronomical phenomena in Vedas and Vedic literature:
Like in any other civilization Astronomical concepts were found in ancient Indian texts.
Stray references to astronomical concepts are found in Vedas and other ancient Indian
literary texts. Vedic texts are repositories of several mythologies developed around stellar
constellations. References to planets, nakstras, motion of Sun and moon are found in Rig
Veda. The details of darsapurnamasa, i.e. the new- and full- moon sacrifices, the
caturmasya or four-monthly sacrifices, seasons, months and month names, are stated
specifically in Yajurveda. The importance of the winter solstice is emphasized through
the mahavrata rites which are also dealt with at length in the Brahmanas of the Samaveda.
The Atharvaveda also contain stray passages of astronomical consequence, such as the
solar eclipse, the mention of Rahu for the first time, intercalation with a thirteenth month
and a list of 28 naksatras including Abhijit.
As part of the Vedic corpus we have two Jyotisa-Vedangas, one in the Yajurveda
recension containing 43 verses and the other in the Rgveda recension containing 36
verses, dealing exclusively with astronomy. The Vedanga Jyotisha, is an Indian text on
Jyotisha (Indian astronomy), redacted by Lagadha. The text is foundational to the
Jyotisha discipline of Vedanga, and is dated to the final centuries BCE. The text describes
rules for tracking the motions of the sun and the moon. In the Vedanga Jyotisha Lagadha
praises astronomy as the crowning subject in the ancillary Vedic studies. In explaining
the scope of astronomy, the Vedanga Jyotisa states: ‘The Vedas are revealed for the
purpose of performing sacrificial rites; these rites are laid down in order of time.
Therefore, he who is versed in astronomy, the science of the reckoning of time, knows
the sacrifices.’ In the Mundaka Upanisad astronomy is included in the list of several
branches of Vedic studies. In the Brahmana literature, we come across the termnaksatradarsa meaning ‘a star gazer’ or ‘a gazer at the lunar mansions’. This term has also been
used sometimes to mean an astrologer. Another term used to refer to an astronomer is
ganaka which literally means ‘a calculator’ or ‘a mathematician’. The use of these two
terms appears to imply the study of astronomy both from the practical (observation of
stars) and theoretical (calculation) considerations.
In the vedic texts, the universe was conceived as of three distinct parts-the earth (prithvi),
the firmament (antariksa) and the heavens (dyaus). The Sun was regarded as the most
important heavenly object and its path, the ecliptic, was considered sacred. The Moon
was the next most important and became the obvious choice for time-reckoning. It was
referred to as masakrt (‘maker of the month’) – the interval between two consecutive new
moons or full moons was taken to be ‘month’. There were two systems of monthreckoning, namely, the amanta and the purnimanta, ending with the new moon and the
full moon, respectively. The Moon’s path was observed in relation to the 27 or 28
naksatras or asterisms and the lunar zodiac was well determined. There is no denying the
fact that, although there were lunar zodiac presentations in Babylonia, China and Arabia,
the method and the manner adopted by the Vedic texts unmistakably point to their
originality. The names of the lunar months were given on the basis of the naksatra in
which the full moon occurred. The twelve lunar months were divided into six seasons of
two months each. There were also special names for the solar months.
There are several references in the Rgveda and in the Brahmanas of the later ages to the
sun’s path through the heavens. It is stated that Varuna, the chief of the Lords of natural
order, has made a spacious pathway for the sun to travel, Zodiac. Observation of the solar
eclipse is recorded in several places in the Vedic literature. The well-known Svarbhanu
legend is one excellent example of description of the solar eclipse with flurish.
According to its earliest Rgvedic version, Svarbhanu, the asura, pierced the sun with
darkness so completely that the bewildered inhabitants on the earth did not know where
they were standing. Then Atri, with the power of his prayer, caused Svarbhanu’s magic
arts to disappear and restored the sun to its brilliance. Pancavimsa Brahmana, of which a
typical description runs as follows: ‘The Daemoniac Svarbhanu struck the sun with
darkness; the Gods did not discern it (the sun hidden as it was by darkness); they resorted
to Atri; Atri repelled its darkness by the bhasa. The part of the darkness he first repelled
its darkness he first repelled became a black sheep, what (he repelled) the second time
(became) a silvery (sheep), what (he repelled) the third time (became) a reddish one, and
with what (arrow) he set free its original appearance (colour), that was a white sheep.’
The interesting feature of the above passage is the detailed observation of the change of
colour in the sun’s disc during the progress of an eclipse.
The antiquity of the Indian naksatra system has been traced to the Rgveda, where the
term naksatra has been used both in the sense of stars and lunar mansions. While the
naksatras are doubtless mentioned in the Rgveda, their whole series, numbering 27 or 28
and headed by Krttikas, turns up for the first time in the Yajurveda. In the Vedic literature
the term naksatra has been used to indicate both asterisms, stars or star-groups, and any
of the 27 equal divisions of the ecliptic, each distinguished by a determinant star (yoga
tara). Derived from nakta-tra, it means ‘guardian of night’, that is stars or star-groups, and
in this sense the word must have been used at the beginning. Later on, naksatra meant
one of the 27 equal parts, that is a space of 13 º 20’ of the ecliptic.
In vedic literature the moon, the most conspicuous object in the night sky, receives such
appellations as candra, candramas and soma. It has no light of its own, but assumes ‘the
brilliancy of the sun’ or ‘is adorned with Surya’s arrowy beam’, that is it shines with the
borrowed light of the sun.
The study of planets appears in late astronomical works. The Vedanga Jyotisa does not
mention them. However, names of planets like Jupiter finds a place in the Vedic corpus.
In the Maitrayani Upanisad, planets (graha) are mentioned. To the seven planets,
including the sun and the moon, the Indians added Rahu and Ketu, to formulate their
Rahu-ketu theories of eclipses. The word Rahu, in the sense of a planet, appears in the
Atharvaveda and the Chandogyopanisad apparently with no astronomical meaning, but in
the Yajnavalkyasmrti it does so in the astronomical sense (as ascending node). The word
ketu also appears in the Atharvaveda in the sense of any unusual or striking phenomenon
such as comet, meteor or a falling star. Astronomical samhitas, however, do not mention
ketu as a cause of eclipse. Rahu and ketu, along with planets, are mentioned in the
mahabharata, though Ketu is omitted in the Ramayana. From Varahamihira onwards, in
true astronomical circles, Rahu and Ketu meant the ascending and the descending node
respectively of the moon. It is in the subsequent Puranic period the Rahu-ketu theories of
eclipses were formulated.
Ancient Indian Astronomy is based upon sidereal calculations. The sidereal astronomy is
based upon the stars and the sidereal period is the time that it takes the object to make one
full orbit around the Sun, relative to the stars. Both ‘day’ and ‘night’ appear as natural
unit of time in the earliest literary productions of the Indians. Expressions like ‘many
dawns and nights’, ‘days subdue the nights’ occur in the Rgveda. Day, that is the bright
half, was divided, according to the Atharvaveda and the Taittiriya Brahmana, into five
parts, e.g udyan suryah (rising sun), samgava (gathering of cows),madhyam-dina
(midday), aparahan (afternoon) and astam-yan (sunset). Further division of the day into
muhurtas and still smaller units has been traced to the Brahmana period. According to
the Satapatha Brahmana, ‘there are ten thousand and eight hundred muhurtas in the year
(1 day = 30 muhurtas), and fifteen times as many Kisprus as there are muhurtas ; and
fifteen times as many idani as there are etarhi; and fifteen times as many breathing as
there are idani’.
In the vedic literature the month was again divided into two natural halves, the light half
(sukla) from new to full moon and the dark half (krsna) from full to the new moon. A
lunar-month was divided into two parts or paksas, the bright half and the dark half of one
lunation, each paksa having 15 tithis, and ingenious devise, which is characteristically
Indian, for calendrical purposes and the names of the paksa following the Sanskrit
ordinals. A day was regarded as consisting of 30 muhurtas, (the longest at the summer
solstice being 18 and the shortest at the winter solstice 12 muhurtas). Several passages in
the Brahmanas point unmistakably to the knowledge of solstices among the Vedic times.
.The increase of day- length from winter solstice to summer solstice and the
corresponding decrease in the duration of the night are recorded in the Jyotisa. Here the
day has 30 muhurtas, the shortest day-length at the winter solstice is given as 12
muhurtas and the longest at the summer solstice as 18 muhurtas. In the Jyotisa we also
find for the first time the rule for determining the length of the day between the two
solstices. The shortest day is given as 12 muhurtas at winter solstice and the longest as
18 muhurtas at summer solstice. In one ayana of 183 days, the day length is said to
increase or decrease by 6 muhurtas, whence the daily increase or decrease works out to
6/183 or 2/61 muhurta.
The year is divided into two halves of six months each marked by the winter solstice
when the Mahavrata rites are performed and by the summer solstice when the Visuvat
day is observed. This is also borne out by the well-known statement of the Vedanga
Jyotisa-prapadyete sravisthadau suryacandramasavudak-(The sun and the moon turn
north at the beginning of the naksatra Dhanistha). When the winter solstice lies in
Dhanistha and the summer solstice in Maghas (14 naksatras ahead), the vernal equinox
must lie in the Krttikas.
The Vedanga Jyotisa records the location of the summer and winter solstices in the
middle of Aslesa and beginning of Dhanistha. From the present positions of the solstices
in the asterisms and from the precessional rate of 1º for every 72 years, it is easy to show
that at about 1400 B.C. the solstices coincided with the middle of Aslesa and the
beginning of Dhanistha. This has led many scholars to suggest 1200 B.C. as the time of
composition of the Vedanga Jyotisa. But the possibility of an earlier tradition being
recorded in the Jyotisa and other internal and literary evidence strongly suggest it to be a
work of the Sutra period, that is after 700 or 600 B.C.
From various stray statements in the Brahmanas, it is possible to infer that the Vedic
Hindus recognized a lunar year of 354 days (12 X 29½), which was adjusted to the
sidereal solar year of 366 days (Vedanga Jyotisa) either by adding 12 days each year or a
thirteenth month of 30 days every 2½ years. The names of the lunar months were derived
from the naksatras in which the full moon occurred, e.g. Phalguna, Caitra, Vaisakha,
Jyaistha and so on from the naksatras Phalguni, Citra, Visakha, Jyestha respectively.
The Vedanga-jyotisa conceived of a cycle of five years, a luni-solar cycle called the yuga,
at the beginning of which the Sun and the Moon would lie at the starting point of the
naksatra Dhanistha. During this period, there would be 5 revolutions of the Sun, 67
Moon’s sidereal and 62 synodic months; 1830 savana or civil days; 1835 sidereal days,
1800 solar days and 1860 lunar days or tithis. The civil day was divided into 30
muhurtas: 1 muhurta into 2 nadika into 10 1/20 kalas; 1 kala into 124 kasthas; and 1
kastha into 5 akssras.
Part II Astronomical tradition in Jaina tradition
The Jainas also claim considerable antiquity for their interest in, and study of, astronomy.
The four branches of their canonical texts include ganitanuyoga (principles of
mathematics), samkhyana (arithmetic) and iyotisa (astronomy). Like the Brahmanas, the
Jainas, too, demanded of their priests great proficiency in astronomy for the proper
observance of their religious ceremonies.
Although the Jainas developed a set of peculiar cosmographical theories which came in
for sharp criticism at the hands of Brahmana astronomers, they adopted and followed,
with minor variations, the Brahmanic astronomy of the Vedanga Jyotisa. The principal
source of Jaina astronomy is Suryaprajnapti, a work divided into 20 books and written in
ardhamagadhi prakrt, which is extant with an elaborate commentary by Malayagiri. Free
from Greek influence, the work was probably written a few centuries before the Christian
era. Its authorship has been attributed to Mahavira. The next important astronomer was
Bhadrabahu (d. 298 B.C.), a srutakevalin and a prominent personage in the history of
Jaina religion. He is believed to be the author of a commentary on the Suryaprajnapti and
of an astronomical samhita known after his name, of which only fragments have been
preserved in later commentaries. Then we have the Jambudvipaprajnapti with a number
of commentaries, of much later date, where elaborate descriptions fo the different dvipas
of the Jaina cosmography are met with.
The peculiarity of the Jaina astronomy consists in its conception of two suns, two moons
and two sets of 27 naksatras. This conception is a consequence of the Jaina cosmography
according to which the earth is regarded as a series of flat concentric rings of land masses
separated by concentric ocean rings. The central circle Jambudvipa, with the mountain
Sudarsa Meru in the centre, is encircled by the salt ocean. Beyond it lies the Dhatukin
Dvipa encircled by the black ocean Kalodadhi and beyond that the Puskara Dvipa
rimmed by an impassable mountain range, the Manusottara Parvata. The innermost
Jambudvipa is divided into four quarters, of which the southernmost part is Bharatavarsa
(India). The sun, the moon and the stars are assumed to move in circles, parallel to the
earth’s surface, round Mount Meru as centre. As Jambudvipa is divided into four
quarters and four directions, and as the sun should make day in succession to the regions
south, west, north and east of Meru, the sun’s diurnal orbit is also divided into four
quarters. Since the length of a day, disregarding variations is 12 hours or 15 muhurtas,
the same sun after making day over Bharatavarsa in the southern quarter cannot reappear
on the following morning as it still has three quarters to travel. To obviate this difficulty,
the theory supposes two similar suns, Bharata and Airavata, separated from each other by
half the orbit, to describe the whole orbit. In this process each sun makes day over
Bharatavarsa on alternate days.
To explain the variations of day length, 183 diurnal circles are imagined. Each sun after
rising in the first circle rises in the next circle each following morning, increasing the
day-length in the uttarayana and decreasing it in the daksinayana by 6 muhurtas, as taught
in the Vedanga Jyotisa.
Part III : Jothisa period gives way to Siddhanthic phase in Indian astronomy
While the astronomical computations enunciated in the Vedanga-Jyotisa continued to be
in use for a long time, possibly during the few centuries preceding the Christian era, there
was emerging a new class of astronomical literature called the Siddhantas. An important
development was the gradual replacement of the naksatra system by the 12 Signs of the
zodiac, Mesa, Vrsabha, Mithuna…..Mina, similar to the animistic notions of the
Babylonians and from them of the Greeks. With the invasion of India by Alexander the
Great in the fourth century B.C. and the subsequent Hellenic and the Hellenistic or
Greco-Roman contacts with India, conceivably the astronomical elements of the former
should have influenced the Indian culture-area.
The newly emerging siddhantas were in the nature of rules or the enunciation of methods
for arriving at solutions of the concerned astronomical problems. According to the Indian
traditional belief, there were principally eighteen such siddhantas, namely, and Surya,
Paitamaha, Vyasa, Vasistha, Atri, Parasara, Kasyapa, Narada, Gargya, Marici, Manu,
Angira, Lomasa (or Romaka), Paulisa, Cyavana, Yavana (or the Greek), Bhrgu and
Saunaka. Five of these Siddhantas, viz., the Saura, the Paitamaha, the Vasistha, the
Romaka and the Paulisa were ably codified by Varahamihira in his Pancasiddhantika (c.
505 A.D.) who has emphasized that the Saura was the most accurate of them all.
With the emergence of Siddhanthic texts and schools, new heights were reached by
Indian astronomy.