Science behind Indic calendar & time-cycle

Students should be aware of the remarkable tradition of science behind our sophisticated cycle of time

The other day I asked a friend where he would be during Jyeshtha? He looked at me uncomprehending, and finally expostulated: “I have no clue about what you are asking, nor what you are trying to get at.” Laughingly, I replied that I was merely speaking of Jyeshtha, a month in the Hindu calendar, which roughly corresponds to May-June.

We don’t have to necessarily follow all the rituals of the past, but we must not be so deracinated as to be completely ignorant of our own heritage (PTI)

I can say with some certainty that most educated Indians, at least in the cities, know nothing or very little about the Hindu calendar. What is it based upon, the lunar or the solar cycle? What is its antiquity? How accurate is it? And what are the months that constitute it? Most of us are completely attuned to the solar Gregorian calendar, although frankly, it is a much later entrant among the global systems of calculation of time. The British used it, and we, as colonial inheritors — at least among the urban educated — simply adopted it and forgot all about the calendar that was used by us since time immemorial.

Although there are variations across India, the dominant Indian calendar is the Panchanga, which was also the traditional calendar in much of South East Asia. It is a lunisolar calendar, essentially based on the moon-cycle, by which a year consists of 354 days, against the Gregorian solar cycle of 365 days. To accommodate this difference, the Panchanga, while maintaining the integrity of the lunar month, adds an extra full month (adhik maas) every 32-33 months, to ensure that the festivals and crop-related rituals fall in the appropriate season. The most known Hindu calendar is the Shalivahana Shaka, devised under King Shalivahana (originating from the Satavahana dynasty, circa 2nd century BCE) of the Deccan region, and the Vikram Samvat, accredited to King Vikram of Ujjain (circa 57 BCE), both of which emphasise the lunar calendar, and are officially India’s national calendar (Shaka). Incidentally, the Chinese, Hebrew and Babylonian calendars are also based on this system. The Islamic or Hijri calendar is also lunar.

What is significant is that the Hindu calendar system substantially predates the Christian era. Vedic scholars had tracked the movement of the sun, moon and other planets to the accuracy of a truti (29.63) microseconds. This was built upon by the prodigious astronomical and mathematical work during the Gupta period (6th to 8th century CE) by scholars like Aryabhata, Varahamihira, and Brahmagupta, further refined later by non-extant works like the Surya Siddhanta, and the writings of Bhaskara II (12 century CE).

Starting from March-April, the 12 Indian calendar months are Chaitra, Baisakh, Jyeshtha, Ashadha, Shravana or Sawan, Bhadra or Bhadon, Ashwin, Kartik, Margshirsha, Paush, Magha, and Phagun. The Indian New Year begins in Chaitra, usually coinciding in the North with the first day of Navratri, nine days after which is the birth anniversary of Lord Ram, Ram Navami. Tulsidasa in Ramcharitmanas describes the date and time of the birth anniversary thus: Naomi tithi madhumasa punita, sakal paccha Abhijit harprita, madhya divas ati seet na ghama, paavan kaal lok bishrama (On the ninth day of the waxing moon of the sacred month of Chaitra, when the moon enters the auspicious group of stars Abhijit, at noon when it is neither too cold nor hot and the world is tranquil, comes the holy moment).

The description clearly marries the movement of the moon, the constellation of stars, and the month of Chaitra. Other parts of India based on similar astronomical calculations, have their own New Year’s Day: Vishu in Kerala; Puthandu in Tamil Nadu; Ugadi in Karnataka; Gudi Pawa in Maharashtra; Pohela Boisakh in West Bengal, Tripura and Bohag Bihu in Assam. In fact, even today, the rhythm of our calendars, and the cycle of harvests, permeate the lifestyle and food choices of millions of Indians. In addition, there are rituals and food prescriptions on ekadashi, the first of every month, purnima or full moon day, and amavasya, the darkest night of the month.

Why is none of this taught in our schools? At least, students should be aware of the remarkable tradition of science behind our sophisticated cycle of time. We don’t have to necessarily follow all the rituals of the past, but must we be so deracinated as to be completely ignorant of what our own heritage and traditions are?

Pavan K Varma is author, diplomat, and former Member of Parliament (Rajya Sabha). The views expressed are personal