Cultural Exchanges & Pluralism

Calendar System : How to Measure Time

Tapas Piplai

So far the calendars were concerned, right from antiquities, the Sun and Moon were taken as two epicentres in ‘time management’ system. Civilisation felt the need to record the changes of events with respect to different time periods. The human civilisation was always at different crossroads and embraced changes to go to higher pedestal of changes for the progress of civilisation. Thus with the growing complexities of civilisation it was felt to identify the ‘time’ or ‘time periods’. The necessity of calendar, thus aroused to plot the changes against a continuous time axis. The world developed various local systems of time measurement on a shorter horizon. But with more exchanges of cross cultural elements with distant human settlements, it was a necessity to have one standardised origin of time and to define the flow thereafter. For standardisation and flow comparison, the units of measurements such as year, month, week etc were necessary to be arrived at. The inevitable conclusion on origin veered around either Sun or Moon or a combined axis in conjunction with earth’s rotation.

Calendar as word has been taken from the word calends which is the first day when the moon is seen during new moon. Initially for keeping the accounts, the term calends used to be coined. The word later was taken over in Old French vocabulary and thereafter by middle English vocabulary in 13th century.

One could find various traces of calendar systems right from Bronze & Iron era of civilisation. There is evidance of the established ancient calendar systems during Babylonian, Persian, Zoroastrian & Hebrew civilisations. Similarly Old Hellenic calendar claims its influence over the origins of Roman and Indian Ancient calendars. Old Roman calendar was reformed by Julius Caesar in 45 BC, and was further rearticulated as Gregorian calendar in 1582 AD after incorporating some correction factors of solar rotations. It became by and large the mostly followed calendar system globally. By the introduction of leap year once in four years the solar calendar severed its ties with lunar system. Similarly on later period the Islamic calendar was formed in 632 AD. It was based on lunar cycle. The rotation of moon around the earth is taken as 27 to 29 days approximately.

The length of rotation time around Sun was calculated in 11th century by a reform team at Persia headed by Khayyam as 365.24219858156 days. It was stated to be changing in sixth decimal place in 900 years and was taken to be as most accurate.

Therefore against global canvas, one finds, various attempts were made to improve  calendar system to a desired accuracy level by taking inputs from different civilisations and the scientific discoveries. No single country or civilisation can perhaps claim as its inventor.

During ancient period in India, from Surya Sidhanta the calendar systems used to be calculated. It was further modified by Aryabhatta (499 AD) followed by Barahamihir in 6th century. Bramhagupta in 7th century and Bhaskara II in 12th century. The main difference was surfaced on defining the origin point and rotation time of earth in seconds accuracy captured in third or more decimal points.

The changes in the relative position of earth, sun, moon, make the changes in the climatic condition of earth . These eventually decide the – harvesting season, rainy season , timing of vegetation of different crops etc. Thus the different climatic conditions herald major social and religious festivals. These festivals are mostly related with the harvesting season.

The new year traditionally starts after spring or during Chaitra month.

Similarly the movements of lunar systems also have been captured while constructing different calendars in ancient India.

The Saka calendar combines the lunar rotation and that of Solar in 365 days by a cmplex mathematical method. The 365 days has been taken as the one full rotation of earth around the sun and termed as one year and the sub-division of the year into twelve months. By and large the lunar systems were captured in defining months and solar system while calculating the year.

The calendar system thus evolved continuously by combining various systems, experimentations and change in climate system.

In India the search of fundamental logic of  solar system was mostly based on mathematical conclusion coupled with logical reasoning rather than on experimentation through observation by any sophisticated instruments. The dedicated people who used to track these astronomical behaviours were called Jyotish expert.

It is extremely difficult to find out the  rotational axis point when Sun , Earth and Moon are all rotating against their own axis as well as against other planets or stars axis in an elliptical path. It is actually Indian's very rich astronomical pursuit from time immemorial that too without any help from any instruments like telescope etc. It was based mainly on shadow movement calculation against time .It was not so easy to define the same 1500 or 1800 years back!

One should be open enough to accord credit to those intellectuals and in turn the kings of yesteryears who used to patronise these scientific pursuits tirelessly. Nothing strictly Hindu or Vedic or Shromonic calendar existed ever in India. It was the intellectual quest of individuals or groups to unearth the reasons behind the physical events. Astrology was the unscientific derivation from scientific astronomical findings. Astrology, Palmistry etc were usually practised by the religious propagandists.

Historians establish the connections between Alexander’s (356-323 BC) invasion and influence from Greece as the refinement influence in India’s calendar system. Puranas and the old siddhantas acknowledge the predominant influence of Greeks, Roman and later Gregorian calendar system in almanacs. Greeks and Arabs also counter-acknowledged and appreciated about Indian astronomical pursuit during the primitive days. From Iran, AI- Beruni paid a visit to India during eleventh century and recorded in his book on Indology a rich tribute to yotish experts and scientists. His book was much circulated later in Europe. Actually Europeans came to know about India’s astronomical and scientific pursuits mainly from his books as these Indian scientists were always publicity shy.

Dr Meghnad Saha, a famous astro physicist from Bengal was appointed and took over as Chairman of the Calendar Committee to standardise calendar system in 1952 across the country. There were more than 30 established calendar systems at that point of time. Apart from that there were large number of local almanacs as well . They all differed on Zero point calculation from astronomical analysis. It was indeed a difficult decision in order to start a new and unified calendar system. One more main difference came in the fractional-time calculation after 365 days of rotation in solar cycle time period. They all predicted some fraction even upto 4th decimal points. But with a gap in accuracy, whatever small it may be, it creates a big difference on a bigger time horizon i.e. over thousand years or more. As a result some calendar lagged and a few had gone ahead of solar cycle time.

La Place, a famous scientist on a much later period appreciated these difficulties and contributed on these correction factor analysis. It used to be corrected through a leap after some time by inserting  Mala Mash in a year as it is used be called. It is indeed interesting to note how these levels of accuracies were arrived at by Barahamihir / Aryabhatta during their time without any help of instruments or telescope!

Interestingly most of these Indian calendars started in the Month of April, the month associated with agricultural production of Ravi harvest or Spring harvest. Again the agricultural productions were in sync with change in climate. The social and religious functions are entailed with these changes and are celebrated with the harvesting season. Thus the new year became a part of social and new harvest celebration.

Later due to religious pressures these calendars were given different names like – Kali, Buddha, Mahaveer, Islam, Saka, Vikram Sambhat etc. ‘Bengali Son’ only remained separate.

Though recent Hindutva wave claims the Kalijug calendar system as the most scientific and oldest but is yet to be validated by any proof. On the contrary the Buddhist and Mahaveer almanacs are appeared to be the oldest Indian calendars with higher accuracy. Saka or Vikram Sambhat calendar system has been started during Gupta period i e 320 - 550 CE.

Later, Akbar (1556-1605 CE) the Mughal emperor worked a lot to combine all the calendar systems under the name – Tarikh e llahi as he was very clear that he was leading a country of multi-races and multi-religions. By the time Mughals came to India, other religions / races were already present in India with their respective calendar systems like Persian, Buddhist, Jain, Judaic Christian etc. These were not only existing but flourishing in India too. So the need had been felt to unify the almanacs into one system. In today’s time the ‘Bengali Son’ is similar to Tarikh ellahi. It was said to be created by Akbar.

In short the calendar system in India underwent several combinations and changes, on the base of India’s multicultural polity even before the colonial power descended on Indian subcontinent with their military might and the draconian concepts of nationalism, religious differentiations, mother or fatherlands etc. Fundamental tradition from debate on such issues since time immemorial were snubbed by imposing the territorial or language identity which eventually converted as nationalism. The concept of newly defined nation is nothing but to protect the identity politics and actually destroyed cultural heritage of pluralism and exchange system. During colonial period the self-rule by the oppressed country emerged as the positive sides of nationalism.

As stated above every new settlement in India brought their own almanac system and added new improvement attributes to the existing calendar system of the country.

One should certainly welcome and appreciate the contributions made by all these clans, be it from inside or from outside the geographical boundaries of  the country. In the name of nationalism or religious identity India must not confine itself within the narrow domestic walls of ignorance and selfidentity pride. Past tradition reaffirms the contribution of plurality of  races and multicultural confluence on  evolved social and cultural fabric.
Note – The book by Prof Amartya Sen – ‘The Country of First Boys’ – is the collection of essays on varied social subjects. One such article is on ‘Calender System’.


Vol. 49, No.48, Jun 4 - 10, 2017