Astronomy of Vedic India
by Eirik L. Harris
From Vedic literature, it can be seen that the ancient Indians were primarily interested in astronomy for its predictive features, its ability to allow them to forecast, in particular, the rainy season, which was of prime importance to all agricultural communities. The ancient Indians named and divided the sky into sections to enable them to better tell time and the coming of the seasons. However, this is not to say that the Vedics were removed from the theoretical or more abstract aspects of astronomical comprehension. There was more abstract Vedic interest, but much advancement in this arena waited until later periods in Indian history. Mythology also played a part in Vedic astronomy, as prominent constellations as well as the five planets visible to the Vedics were thought of as gods.
The ancient Indians divided the path of the moon into 27 equal parts called nakshatras, showing the variation of the relative position of the moon in comparison to the rest of the stars visible to the Vedic people. These nakshatras were quite important for determining times of the year, as can be seen in combination with Vedic mythology, and can also be used to determine how far back in history Vedic astronomy extended.
The myth of the god Janus shows both of these factors, the determination of the age of Vedic astronomy and different periods of the year. Janus had four heads, each of which represented a phase of the moon in Sagittarius (one of the nakshatras) which marked the four seasons. One head was the full moon (in Sagittarius) which gave the time of the spring equinox, another was the new moon, during which time the autumn equinox fell, still another was the half waning moon, marking the winter solstice, and finally came the head representing the half waxing moon, during which time came the summer solstice. From current knowledge of the movement of the sphere of stars surrounding the earth, it can be calculated that the observations leading to the myth of Janus were made around 4000 BC. Additionally, within the Rg Veda is a verse observing the winter solstice in Aries, which would have placed it at around 6500 BC.
It is possible to date the Rg Veda like this because a complete cycle in the procession of the equinoxes takes place either every 25,870 to 24,500 years according to modern astronomers (the exact time period is still disputed by modern day astronomers), meaning that the moon is only full in Sagittarius during the spring equinox every 25,000 years or so. Modern astronomers, however, were not the first to make the difficult calculations to discover the length of this cycle. The Vedics were able to do this and came up with the value of 25,870 years. How these ancient people were able to make these calculations, however is "as great a mystery as the origin of life itself".
Further observations which could only have taken place around 4000 BC have also been recorded. These included the constellation Hydra, the god of darkness. The only time Hydra was fully visible to the people of northern India was in mid-winter, when the sun shone the fewest hours, hence the allusion to the god of darkness. More importantly, however, was the fact that the rains came when Hydra ceased to be completely visible. This was very important to the farmers of North India, for they needed to know when the rains would come, so as to know when to prepare their fields and plant their crops.
While agrarian life played a large part in what aspects of astronomy were most important, it would be incorrect to assume that Vedic people were only interested in how astronomy related to their lifestyle. Unlike other societies, the Vedics did not mark their nakshatras with lines of any sort. Rather, their divisions were more open in that each nakshatra was represented by regions consisting of groups of stars as well as single stars which with no clear cut divisions. Ancient Indians even went so far as to catalogue the prominent stars in each nakshatra and classify them in terms of their brilliance. Additionally, these nakshatras were classified as male, female, and neuter, as well as singular, dual, and plural. This overlaps with their view of the planets as gods and hints that the Vedic people thought of the nakshatras as deities as well.
These practices all show that astronomy was not only valued for its immediate usefulness to the Vedic farmers, and additional information supports this. Vedic astronomers recognized and noted many of the constellations known in modern times, including what are now know as Canis Major and Minor, the Great and Little Bears, Argo Navis, Orion, and Sirius. Additionally, the Vedic people knew that the moon shone by reflecting the light of the sun, and not by its own light, they thought of the universe as infinite, and they noted meteorites and comets as well as at least five eclipses in addition to five planets. Thus the idea of the Vedic people's intrinsic interest in astronomy for interest rather than for pure usefulness can be supported.
Returning to the calendar, the Vedic people divided day and night into 15 parts each, and the year into six seasons of 61 days total, each of two solar months. Solar years were also grouped in sets of five, or yugas. Solar calendars were not the only type of calendars utilized by the Vedics, however, lunar calendars were also used, and an additional lunar month was added to lunar years every 30 lunar months in order to keep a synchronization between lunar and solar years. These were quite accurate, but did give discrepancies. A solar yuga was in actuality 1826.2819 days rather than 1830 and there were 1830.8961 days in 62 lunar months, not 1830, giving a deficit of approximately one tithi (a new or full moon day) per solar yuga in the latter case. While these discrepancies must have been rectified, there seems to be no record of how or when this was done. This is due most likely to the fact that only religious texts of the period have been recovered. These texts were, of course, not interested in mathematics or astronomy in itself, rather only in how it related to mythology, religion, and living conditions. Thus, records of calculations were not included in the Vedas.
Another prime use of astronomy was, as was the case in many cultures, religious. In fact, the first text to deal solely with astronomy, the Ve danga-jyautisa which can be dated at around 1150 BC by looking at the positions of the sun and moon in the yugas mentioned in the text. This text defines astronomy as the science of time determination and gives the measure of the water clock, tells when intercalary months should be added or a tithi omitted, and other information which would have been necessary for Vedic priests to predict times for vedic sacrifices and other religious observances.
Additionally, it is interesting to note that the Vedic people thought of time as relative, for, according to the Rg Veda, the sun made the division between day and night, which was of two types, those of men and those of gods (A year was a day and a night for the gods). It was further postulated that the age of the gods (two thousand of their years) multiplied by 71 formed a manorantara, or cycle. These cycles alternatively brought about the creation and destruction of worlds, and continued on indefinitely. This is interesting not only as an indication of their view of the universe, but also as an indication in the scope of their thinking. It can be presumed that our earth was not the first of these cycles, and thus that they thought of the universe as being more than 730 thousand years old, a very long time to conceptualize. It is almost impossible to come up with information on pure astronomy in the Vedic period of India since the only texts which appear to have survived are the Vedas, which were more concerned with religion and mythology than pure astronomy. Additionally, the texts on astronomy, such as the Ve danga-jyautisa, deal with astronomy in relation to the Vedic religion. Even the definition of astronomy in this book, "the science of time determination" shows that it will not contain information relating to all aspects of astronomy as it is known today. From what can be gleaned from the Vedas, however, it can be seen that the Vedic people were interested in astronomy for what it could give them in the way of predictive powers and religious calendars. It is interesting, though, that abstract thinking did enter into the minds of the Vedics, in their thinking of the universe as infinite. Additionally, the Vedics, who developed the Hindu-Arabic number system, were far enough advanced in mathematics to make many calculations, including that of the complete cycle of the progression of the equinoxes, though, again, as the Vedas were mainly religious, there is no mention as to how results like this were derived. Overall, the Vedic culture was very rich in astronomical thinking, and it is a shame that non religious texts did not last through the centuries, for they could have shone more light on the matter of the astronomical accomplishments of the Vedic people.
A Brief History of Astrology (on internet)
A History of India and Hindu Dharma (Copyright 1994, Himalayan Academy - on internet) . Bag, A. K., Shukla, K. S., Swarup, G., ed.
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Histoire de l'Astronomie depuis ses Origines Jusqu'a nos Jours, Paris: Librarie Hachette, 1873. Plunket, Emmeline M.
Ancient Calendars and Constellations, London: John Murray, 1903.