Ancient Indian Science

Hindu calendar: Its complexities & benefits

Humankind has always been fascinated by all things that spur wonder; none more so than the concept of time and space. There have been multiple space explorations and inspired stargazing has always been done to search for patterns, regularities and the irregularities, periods, and intervals in order to measure time in congruence with the astronomical phenomena. With the evolution came the desire to linearize the time-scale in order to calibrate it with the path and duration of the sun, moon, and stars.

Calculation and computation of time has been deemed as a hallmark for all ancient civilizations. Egyptian and Mesopotamian civilizations surely had interest in chronology and astronomy, but it was in the oldest and the largest one, the Indus Valley civilization that human surpassed the acumen. The employment of professional astronomers called ‘nakshatra darshaks,’ that later got interpreted as ‘stargazers,’ shows how invested the Indian were. The meticulous observations and records of the phases of the moon in reference to the fixed constellations led to a method of precise calculation that definitely distinguishes Indian astronomy from the rest.


In the present day around the world, the Gregorian calendar has become the norm.  It was proposed by Pope Gregory XIII in 1582. It’s a modified version of the calendar established by Julius Caesar who had, in turn, based it on the ancient Egyptian calendar. The non-Catholic countries were, but of course, reluctant to accept it and it wasn’t until the turn of the 20th century that Russia and Greece converted to the system. England joined the party even later in 1752. Christians didn’t warm up to the idea because the New Year’s Day, which had until then been celebrated on 25th March, had to be moved to 1st January. Easter Sunday proved to be yet another matter of discontent as the Christian ecclesiastical or church calendar was originally based on the belief that Jesus’ resurrection was on a Sunday so Easter should always be on that day. The Sunday following the first full moon after the spring equinox was decreed to be regarded as Easter Sunday. The date still varies because important factors of lunar period weren’t taken in to consideration.

It is also to be noted that the current Gregorian calendar commences from the ‘year of grace’ which signifies the year in which Jesus was born. This beginning of the Christian era is denoted by the year followed by the initials ‘A.D.’ that stands for ‘Anno Domini.’ Latin translation of it means ‘in the year of our Lord.’ But the Bible clearly references to Jesus being born during the reign of King Herod who died in 4 B.C.! It was much later on that the whole of Christendom came to accept that he was born between 8-4 B.C.

In contrast to this comparatively ‘modern’ conflict, references from Vedic literature show that the knowledge of chronology (science of time) and chronometry (scientific measurement of time) existed as early as the Vedic times that pre-date the Christian era by thousands of years. During the Vedic age the knowledge of planetary motions, constellations, eclipses, solstices, seasons, etc., was already there. A time distribution method was devised to intimately connect with the regular affairs of the people by dividing it into various periods such as days, fortnights, months, and years. The fact that the Hindu calendar, or Panchang, was conceived to serve the day-to-day affairs and not just allay religious matters, it was allowed to be both lunar and solar. The Rigveda clearly cites months being lunar and years being luni-solar.

The limitations of the Gregorian calendar

With its basis on the solar cycle only and no regard for the lunar one, two main shortcomings come to fore:
1. The determination of the date of a certain day by merely observing at references in the sky is not quite precise or simple, and
2. The months all have different number of days which adds a lot of complexities, like if one is paid monthly you end up doing different amounts of work each month for the same remuneration. Or despite people having made ways around it, the monthly sales comparisons remain difficult for businesses as the number of days vary.

How does Panchang work and its advantages

The Hindu calendar is lunisolar which combines lunar and solar calendar with its months based on the lunar cycle. The Hindu mathematicians divided the zodiac into 12 equal parts called rashi. Each one is divided into 30 parts. Entry point of the time of sun to any new rashi is called Sankranti. From one Sankranti to just before the next is one Solar Month. Therefore, the months are zodiac based and they seem long when the sun is far from earth and they are short when it is nearer. A complete revolution of moon to earth is the Lunar Month. This revolution starts from point of the new moon hence implying that new moon to just before the next is one lunar month. This lunar month normally starts in one solar month and ends into another meaning from one to the other is when a Sankranti falls. The sequence thus becomes: Sankranti – New Moon – Sankranti – New Moon and so on. Within nearly 3 years, a full length of lunar month falls in a solar month. In that situation the sequence changes to: Sankranti – New Moon – New moon – Sankranti. This ‘extra’ month is given to the God and in the period no religious activities are carried out. The reversal position occurs some times normally repeated in 19 or 141 years as New Moon – Sankranti – Sankranti – New Moon wherein a solar month collapsed into a lunar month.

There is another aspect to be looked in to. The moon keeps changing its shape from new to full and so on. This cycle takes 29.53 days. In the Hindu calendar a month is equal to this making all of them the same length. Thereby by just looking at the moon one can figure out what date it is. A new moon is Amavasya and a full one is Poornima.

All of 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 form a lunar year of 354 days 8 hours 48 minutes and 36 seconds. To make the lunar months coincide with the solar year, the practice of inserting intercalary (extra) months was brought about. Simple calculations reveal that 60 solar months are equal to 62 lunar months. Therefore, an extra month, called the Adhik Maas is inserted every 30 months or approximately every 2½ years. This practice, once again, was prevalent even in Vedic times. This intercalary month 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 well thought out inclusion of intercalary months to the lunar months makes sure that the festivals don’t fall at different times of the year, every year. This is exactly what is lacking in the lunar month system as is followed in the Islamic calendar. The Muslim festivals such as Eid and Ramadan never fall at the same time every year due to this oversight.

Another benefit for these adjustments on month, days etc., are to maintain exact seasons in both solar and lunar calendar system.

It is also noteworthy as to how intricate the Hindu calendar is. It offers a very multi-dimensional method that structures time combining information about both solar and lunar days, as well as, months with the movements of the sun and the moon in relation to stellar constellations, and other astronomically defines time spans. This makes it significantly more complex.

It is also true that there isn’t one, single Hindu calendar. The Indian National Calendar or Saka calendar, that came about in 1957, is the official standardized version that represents one of many variations. Each region uses its own variant of the ancient system predominantly based on the cultural as well as agricultural harvest season. Taking an example of the start of a new year, in most regions it does so when the New Moon before the sun enters the zodiac sign of Aries (Mesh). This happens on or around the days of the March Equinox which marks the beginning of spring in the Northern Hemisphere. The grains are harvested and the new season of sowing starts. It follows the Spring Equinox and generally falls on the 14th of April of the Gregorian calendar. This date is observed as the traditional new year in not just Assam, West Bengal, Kerala, Tamil Nadu, Manipur, Tripura, Bihar, Odisha, Punjab, Uttar Pradesh, Uttarakhand, Himachal Pradesh, Haryana, and Rajasthan in India; but also in Nepal, Bangladesh, Myanmar, Cambodia, Laos, Thailand, and Sri Lanka. There are some common features that are still maintained across the variants.

The ‘modern’ application

The Hindu calendar i.e., Panchang may have been mainly reduced to only being used to determine the dates of Hindu festivals and when to observe fasts, the importance can not be watered down. Even in the modern-day India, people see astrologers to seek advice or counsel on remedies, match-making, muhurat (auspicious time) etc., for starting new ventures. The very first thing an astrologer does is to open the Panchang followed then by mathematical calculations, and checking malefic and benefic positions of the grahas (planets). For the benefit of the common people who don’t have the exact know-how of the system, astrologers devised the Panchang based on their knowledge of arithmetical calculations.

It is not necessary for a common person to fully understand the Panchang but for a systematic and smooth running of life, it is at least worth being aware what the five ‘angas’ or components, called Phalita, are that contribute to its formation:

1. Tithi: The ‘date’ is considered as the first phase or portion (kala) of the 16 phases of the moon
2. Nakshatra: The 27 groups of stars (constellations) determine these
3. Yoga: These are 27 in number and are based on combinations
4. Karan: These can be movable or fixed and are half of the part of Tithi
5. Vaar: The seven days of a week

These ‘angas’ primarily help in finding days or dates that are auspicious or inauspicious as starting important work or endeavours at the specified times can make the difference between successful accomplishment or obstructions causing hurdles in the achievement as per the tried-n-tested systems. The planetary positions and the different permutations all come together to make such decisions.
In summation,the comparison yields that the Gregorian calendar may be more accurate in terms of representing seasons but the Panchang covers more ground and is surely more resolved in its composition with respect to offering a scientific time reference method.

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