WHAT IS SO RIGHT ABOUT THE HINDU CALENDAR?

Time and space are two wonders, which extends infinitely behind and ahead of us at the same time. It has made human wonder and explore the outer realms of space and gaze at stars as if to search for patterns, regularities, periods and intervals. He sought answers on how to measure time, in the astronomical phenomena manifesting in the sky.

The primitive man hunted during the day and rested in the night. But, when he transformed from a hunter to a farmer growing crops, he inevitably needed to relate his agricultural operations to the sun and the moon. He started observing the cyclical pattern in seasonal changes and in the waxing and waning of the moon. The necessity of a developing a framework for time-keeping increased, as man grew as a social animal and engaged in more trades. To linearize the time-scale, he sought to calibrate it with the path and duration of sun, moon and stars in the sky.

Computation and calculation of time was a hallmark of all ancient civilizations. Egyptian and Mesopotamian civilization had their abiding interest in chronology and astronomy. The oldest and the largest civilization, the Indus valley civilization, was by far the most advanced and sophisticated in terms of chronological and astronomical acumen. They even had professional astronomers, called ‘nakshatra darshaks’ or ‘star gazers’, who meticulously observed and recorded the phases of the moon in reference to fixed constellations of stars. This method of calculation and its precision, sharply distinguishes Indian astronomy from the astronomy of all other countries.

How is the Hindu calendar different from Western calendar?

Difference of Western and Indian calendar lies in the frame of reference. The western calendar is based on the sun, where a year is defined as the time taken by the earth to traverse one orbit around the sun. Advanced scientific instruments have measured this to be precisely 365 days 5 hours 48 minutes and 46 seconds. This solar year comprises of 12 arbitrarily designated months — all of which have either 30 or 31 days, except February, which has 28 in common years and, 29 every fourth year (called the leap year).

The Indian calendar is ingeniously based on both the sun as well as the moon. It uses a solar year, but divides it into 12 lunar months. A lunar month, is the time required for the moon to orbit once around the earth and pass through its complete cycle of phases. Furthermore, these months are formulated in accordance with the successive entrances of the sun into the 12 rashis or the signs of the zodiac derived from the 12 constellations marking the path of the sun.

Origins of Gregorian and Hindu calendar system

A brief historical preview of the Western calendars will help explain why the Indian system is so precise and scientific. The present day western calendar has its origin from the ancient Roman calendar. The term ‘calendar’ has it origin from the first month of Roman calendar- ‘Kalendea’. In 46 BCE, Julius Caesar announced a reformation in the system of dating, called the Julian calendar. It was the Greek astronomer, Sosigenes, who advised Caesar to have this new calendar, because he calculated the length of the solar year to be 365¼ days. To compensate for errors that had accumulated over previous years, Caesar decided to allocate 445 days to the first year. Not surprisingly, 46 BCE later became infamous as ‘The Year of Confusion’. Unfortunately, because of other misunderstandings, the new calendar was not in smooth operation until 8 CE.

In 730 CE, St. Bede the Venerable, an Anglo-Saxon monk, miscalculated and announced that the 365¼ day Julian year was 11 minutes and 14 seconds too long. On the basis of Bede’s calculation, the accumulative effect of the error in Julian calendar had shifted the dates by 14 days, by the 16th century. Displacement of almost a day per century! Pope Gregory VIII in 1582 and ordained a reformation to restore the calendar to its ‘correct’ schedule. The resolution from the Pope Gregory too was flawed because he estimated only a 10-day adjustment. And so the change was effected, by advancing the calendar by 10 days on 4th October 1582. The following day became 15 October 1582! The foibles in the omission and commission, was so evident that the vernal (spring) equinox which occurred on 21st March in 325 CE had shifted to 11th March in 1582!

Needless to say, the non-Catholic countries were reluctant to accept the new Gregorian calendar. It was not until the turn of the 20th century that Russia and Greece converted to Gregorian calendar system. England, too, adopted it very late in 1752. Many Christians abhorred the new system, because the New Year’s Day, which had until then been celebrated on 25th March, had to be moved to 1st January. The major bone of contention though was the Easter Sunday. The Christian ecclesiastical (church) calendar was originally bound by the belief that Jesus’ resurrection was on a Sunday, and so Easter should always fall on a Sunday. Later, it was decreed that the Sunday following the first full moon after the spring equinox should be regarded as Easter Sunday. Despite all this, though, the date still varies from astronomical reckoning because certain important factors of the lunar period were not considered.

The present day Gregorian calendar commences from, the ‘year of grace’, which signifies the year in which Jesus was born, and the beginning of the Christian Era. The year is followed by the initials ‘AD’ which stand for ‘Anno Domini’, which in Latin means ‘in the year of our Lord’. But the Bible clearly gives reference to Jesus being born during the reign of King Herod, who died in 4 BC! All of Christendom now universally accepts that Jesus was born between 8–4 BC.

On the other hand, references from Vedic literature show that the knowledge of chronology (science of Time) and chronometry (scientific measurement of Time) existed even during Vedic times, thousands of years before the Christian era. Knowledge of planetary motions, constellations, eclipses, solstices, seasons, etc. has existed since the beginning of the Vedic age. A method of distributing time into various periods such as days, fortnights, months and years was adopted for the purposes of civic life, these divisions being intimately connected with the affairs of the people. And because of the very fact that the Indian calendar was devised to serve the affairs of day-to-day living, it was allowed the freedom of being both lunar and solar. The Rig Veda, cites months being lunar, but years luni-solar.

This means that there was a constant correlation between the solar year and its monthly lunar divisions. A lunar month is precisely 29 days 12 hours 44 minutes and 3 seconds long. Twelve such months constitute a lunar year of 354 days 8 hours 48 minutes and 36 seconds. To help the lunar months coincide with the solar year, the practice arose of inserting intercalary (extra) months. In general, 60 solar months = 62 lunar months. And so an extra month, called the Adhik Maas (extra month), is inserted every 30 months, approximately every 2½ years. Such a practice was prevalent even in Vedic times. An intercalary month mentioned in the Rig Veda {Vedamãso dhrutavrato dvãdasha prajãvatah; vedã ya upajãyate. (I/25:8)} proves that the month was added to preserve the correspondence between a whole solar year and the 12 lunations.

Such an adjustment assures that the seasons, festivals, etc. retain their general position to the solar year. That is why, for example, Diwali always falls between late October and early November. The omission of intercalary months to the lunar months would have resulted in festivals falling at different times of the year, every year. This is exactly what is lacking in the lunar month system followed according to the Islamic calendar, wherein Muslim festivals such as Eid and Ramadan never fall at the same time every year.

A lunar month is divided into 30 lunar days. Lunar days in the Indian calendar are called tithis. They, too, are calculated very scientifically using the difference of the longitudinal angle between the position of the sun and the moon. Each tithi is defined by the time required for the longitude of the Moon to increase by 12° over the longitude of the sun. The Vedic astronomers had knowledge the orbit of the moon around the earth was elliptical and calculated the duration of each lunar day(or tithi). The length of a tithi was allowed to vary in length from about 20 hours to nearly 27 hours. That is why we find at certain times, a tithi being ‘omitted’, and at certain times, two consecutive days sharing the same tithi.

Ancient Indian astronomers had terms for measurements of time as minute as 34,000th a second! The precision, accuracy and scientifically-proven system of Hindu calendar became popular in Nepal, Tibet, Thailand, Java, as well as the Islamic West and other regions of south-east Asia. Several Indian texts on astronomy got translated into Chinese, during the Sui and Thang Dynasties (581–907CE). Foreign astrologers and astronomers were attracted to India from as far as Persia and Arabia. David Pingree noted this positive influence during his extensive study of the history of Indian literature. He writes in Jyotishastra — Astral and Mathematics Literature, Volume IV- “The basic traditions of Indian astronomy imposed on these external [Babylonian, Greek and Islamic] systems its peculiar stamp, and transformed the science of Mesopotamia, Greece and Iran to something unique to India.”

The two-part lunar month

In the Indian calendar, the month follows the phases of the moon. The interval between two consecutive new moons (no moon) or full moons was the basis of calculating the length of a month. Two systems of month-reckoning were prevalent in different parts of India at different times: the Purnimanta system — in which the month ends with a full moon; and the Amasanta system — in which the month ends with a ‘no moon’ night. Each month is divided into two parts or pakshas- the Shukla paksh and the Krishna paksh. When the moon waxes from new moon to full moon, it is the Shukla paksh (light lunar fortnight). When the moon wanes from the full moon to the new moon, it is the Krishna paksh (dark lunar fortnight). Each paksh is consisting of 15 Tithis. The first day of Shukla paksh starts with Amavasya (‘no moon’) and reaches Purnima (full moon) on the 15th tithi, thereafter starts the first day of Krishna paksh, which ends in new moon on 15th tithi of Krishna paksh. This system of dissecting a month equally into two, and again into 15, is a truly ingenious, logical and simple.

The seven day week

The Hindu calendar system as per the Vedic scriptures does not have any mention about a week concept. This concept of a seven-day clustered week was adopted from the Greeks around third century CE. Vāsara or Vara refers to the weekdays whose names are based on zodiac planets. The Hindu names of the week show great correlation with other Indo-European calendars. For example the latin name of monday being Lunae, which means the moon, whereas the Sanskrit equivalent is ‘Soma’, and hence monday is ‘Soma-Vāsara’

Just like months, the Hindu calendar has two measures of a day, one based on the lunar movement and the other on solar. The solar day or civil day, called divasa, has been what most Hindus traditionally use, is easy and empirical to observe, with or without a clock, and it is defined as the period from one sunrise to another. Traditionally, and quite logically it seems, a new day begins at sunrise (not midnight), and the night, at sunset (not after noon or evening).

Seasons within the Hindu calendar

It is even more interesting, how the solar year was classified on the basis of seasons. The 12 lunar months of a solar year are divided into six ritus (seasons), each comprising of approximately two months. Since the seasons are solar based, each of the six seasons — Sharad (late monsoon), Hemant (early winter), Shishir (winter), Vasant (spring), Grishma (summer) and Varsha (monsoon)- commence around the 21st date (±2) of each even month of the Western calendar.

The Hindu calendar recognizes the importance of the summer solstice and winter solstice in a solar year, determining the six seasons. The Dakshinayana or the sun’s southern course starts from June 21 till December 21, during which the day-length is successively getting shorter until it is the shortest in december. The Uttarayana or the sun’s northern course progresses from December 21 until June 21, during which the day-length gets successively longer until it is the longest in June. Sun reaches the equinox twice in a year, during which the length of day and night are equal. The first point is Vernal Equinox in March 20(Vasant Sampaat). The other point is called Autumnal Equinox in September 22(Sharad Sampaat).

When does the year start?

The start of the year varies from one region to another, predominantly based on the cultural as well as agricultural harvest season. In most regions, the year starts on the New Moon before the Sun enters the zodiac sign of Aries (Meṣa). This happens on or around the day of the March equinox, which marks the beginning of spring in the Northern Hemisphere. It is during this time of the year that the grains have been harvested and the new season of sowing starts. It follows the spring equinox (Vasant Sampat) and generally falls on 14 April of the Gregorian year. The same date is observed as the traditional new year in Assam, West Bengal, Kerala, Tamil Nadu, Manipur, Tripura, Bihar, Odisha, Punjab, Uttar Pradesh, Uttarakhand, Himachal Pradesh, Haryana, Rajasthan as well as in Nepal and Bangladesh. Myanmar, Cambodia, Laos, Thailand, and Sinhalese in Sri Lanka also celebrate the same day as their new year.