Astronomy is one area which has fascinated all mankind from the beginnings of history. In India the first references to astronomy are to be found in the Rig Veda which is dated around 2000 B.C. Vedic Aryans in fact deified the Sun, Stars and Comets. Astronomy was then interwoven with astrology and since ancient times Indians have involved the planets (called Grahas) with the determination of human fortunes. The planets Shani, i.e. Saturn and Mangal i.e. Mars were considered inauspicious.
In the working out of horoscopes (called Janmakundali), the position of the Navagrahas, nine planets plus Rahu and Ketu (mythical demons, evil forces) was considered. The Janmakundali was a complex mixture of science and dogma. But the concept was born out of astronomical observations and perception based on astronomical phenomenon. In ancient times personalities like Aryabhatta and Varahamihira were associated with Indian astronomy.
It would be surprising for us to know today that this science had advanced to such an extent in ancient India that ancient Indian astronomers had recognised that stars are same as the sun, that the sun is center of the universe (solar system) and that the circumference of the earth is 5000 Yojanas. One Yojana being 7.2 kms., the ancient Indian estimates came close to the actual figure.
The Calculation of Eclipses And
The Earth's Circumference
In Indian languages, the science of Astronomy is today called Khagola-shastra. The word Khagola perhaps is derived from the famous astronomical observatory at the University of Nalanda which was called Khagola. It was at Khagola that the famous 5th century Indian Astronomer Aryabhatta studied and extended the subject.
Aryabhatta is said to have been born in 476 A.D. at a town called Ashmaka in today's Indian state of Kerala. When he was still a young boy he had been sent to the University of Nalanda to study astronomy. He made significant contributions to the field of astronomy. He also propounded the Heliocentric theory of gravitation, thus predating Copernicus by almost one thousand years.
Aryabhatta's Magnum Opus, the Aryabhattiya was translated into Latin in the 13th century. Through this translation, European mathematicians got to know methods for calculating the areas of triangles, volumes of spheres as well as square and cube root. Aryabhatta's ideas about eclipses and the sun being the source of moonlight may not have caused much of an impression on European astronomers as by then they had come to know of these facts throught the observations of Copernicus and Galileo.
But considering that Aryabhatta discovered these facts 1500 years ago, and 1000 years before Copernicus and Galileo makes him a pioneer in this area too. Aryabhatta's methods of astronomical calculations expounded in his Aryabhatta-siddhanta were reliable for practical purposes of fixing the Panchanga (Hindu calendar). Thus in ancient India, eclipses were also forecast and their true nature was perceived at least by the astronomers.
The lack of a telescope hindered further advancement of ancient Indian astronomy. Though it should be admitted that with their unaided observations with crude instruments, the astronomers in ancient India were able to arrive at near perfect measurement of astronomical movements and predict eclipses.
Indian astronomers also propounded the theory that the earth was a sphere. Aryabhatta was the first one to have propounded this theory in the 5th century. Another Indian astronomer, Brahmagupta estimated in the 7th century that the circumference of the earth was 5000 yojanas. A yojana is around 7.2 kms. Calculating on this basis we see that the estimate of 36,000 kms as the earth's circumference comes quite close to the actual circumference known today.