Tiruvallur, a town near Chennai, Tamil Nadu was a center of Panchang makers and likely Astronomy in the past. Many do not know why and what the Panchang makers rectified in the recent. Let us explore both these.
European sailing expeditions in the fifteenth and the sixteenth centuries faced severe impediments because of poor nautical maps. Therefore, the Spanish, Dutch, French and British kings offered huge prize money for anyone who could produce reliable navigational charts. Consequently, a few Jesuits scholars traveled to India to study the Hindu Panchang system. They had heard of the use of ready made tables in the subcontinent to produce accurate calendars. Besides these tables were based on local “longitudes”. The longitude basis of these tables was of value to the Jesuits.
The information which the Jesuits gathered was valuable to European astronomers. For example. the Famous astronomer Cassini consulted the famous Siam Table. Some other astronomers used tables from Krishnapuram and Tiruvallur tables. These three tables were known for their accuracy. This attests to Tamil Nadu, especially Tiruvallur being an astronomy hub, a few centuries ago. An interesting Panchang revolution took place two hundred years later close to Tiruvallur.
By the close of the 19th century Hindu calendar makers had forgotten an important principle of predicting the position of planets. Consequently their calculation of the start of the Hindu year itself was off by three days. In addition, Panchang calendar were off in their prediction of the solar eclipse for the year 1878. They were off by as much as 24 minutes.
Panchang formulae and the Bija seed
Ragoonathachary, who hailed from a family of Panchang makers, proposed a revision to the Panchang tables. He recognized an error in the Bija or the “Seed” value for the formulae used in calculating the current position of the planets. Nobody had adjusted this Bija seed value for a couple of centuries. Consequently, Panchang makers of the nineteenth century were using outdated formulae. Ragoonathachary, a prudent observer, reminded others of this fact. He also said that astronomers like Aryabhata and Brahmagupta had emphasized the importance of updating Bija Values. Certainly, there was an earlier tradition of making fresh set of accurate observations, periodically, for the purpose of calculating new Bija values. Normally, such observations took place 2-3 centuries apart.
Ragoonathachary’s proposals created a controversy among the elite Hindus. Some saw him as an agent of the British. Certainly, their doubts were justified because the colonial Government had issued a proclamation in 1878 for all Panchangs to switch to the Gregorian system of time keeping. Ragoonathachar realized the need to rally the support of Hindu Pontiffs first, to convince the hardliners. Secondly, he needed this support to remind his opponents about the forgotten aspect of the native astronomical traditions.
Certainly, the Pontiffs of prominent Shaivite and Vaishnavite Mutts had a fuller knowledge of the traditions than the elite. Besides they had an open mind. Subsequently, they suggested a smart way to bring everyone on board. Consequently, the Drik (Observation Oriented) Panchang became a part of modern Hindu tradition. Hindu Panchang today is a mix of the modern and the ancient. For example, it borrows data from modern astronomical observations and derives the Sacred time elements of the Hindus as before.