History, Science, Importance and Calculation of Indian Calendar System

Calendar, the system followed across the world which helps to divide and organize time period in days, week, month and year. We cannot think of without calendar for even a moment in our day to day life which helps us to plan in our day to day life

Need of Calendar in day to day life of every individual on earth

Diversity of the life observed over human evolution led primitive men to realize the need to calibrate divisions of time. Thoroughly monitoring of sun and moon allowed to determine cycle of day and night, and appreciate consistency of seasons. The Indus Valley Civilization (of India) occupies pre-eminent stance in terms of chronological and astronomical discernment..

Various types of Calendar follow across the World

All types of Calendar system worldwide can be categorized, based on astronomical years which depends on movement of celestial bodies, mainly under 3 types as below.

Luni-Solar Calendar system

Luni Solar system takes both Sun and Moon into consideration. It uses the solar year but divides it into 12 lunar months. The definition of a lunar month is the time required for the moon to orbit once around the earth and pass through its complete cycle of phases. At the same time this month also considers successive entrances of the sun into 12 rashis – signs of the zodiac, i.e. the 12 constellations marking the path of the sun.

Solar Calendar system

Solar System ignores Moon completely and it is based on Sun only. One Year in solar system is the time that earth requires to complete one orbit around the sun, which exactly is 365 days 5 hours 48 minutes and 46 seconds.

Lunar Calendar system

Lunar system ignores Sun completely and it is based on Moon only. The lunar calendar uses the phases of the moon to measure time, usually measuring the time from new moon to new moon as one month.

Common confusion regarding terminologies used with years.

AD (Anno Domini), BC (Before Christ), BCE (Before Common Era) and CE (Common Era). Here AD is same as CE and BC is same as BCE. Generally AD is written before the year, while BC, BCE, and CE are all written after the year.

For example :-

2008 - Barack Obama wins the AD 2008 election, becoming the first African American President.

2017 - PSLV-C37 successfully carried and deployed a record 104 satellites in sun-synchronous orbits in 2017 CE.

1006 BCE—David becomes king of the ancient United Kingdom of Israel in 1006 BCE.

Origin of Vikram Samvat Era (विक्रम संवत्)

The one of the greatest ruler of BharatVarsha, King Vikramaditya was born into the Gardabhilla royal family and grew up to be a noble and renowned ruler of the Malwa region, its capital being the picturesque city of Ujjain.

The King Vikramaditya started Vikram Samvat in 57 BC and it is believed to be based on the commemoration of King Vikramaditya expelling the Sakas from Ujjain in 56 B.C. and hence Indian Calendar is 56.7 years ahead of the solar Gregorian calendar.

Difference between Western year and Indian Calendar / Hindu Calendar (Vikram Samvat)

The era currently popular in the Indian calendar is the Vikram Era, or Vikram Samvat as it is called.For calculation of corresponding year of Common Era (CE), 57(in certain cases 56) years should be subtracted from the Indian Calendar or Vikram Samvat.

When to deduct 57 years ?

When the date falls between the beginning of the Indian Calendar year (Kartik sud 1) and the end of the Western year (31 December).

When to deduct 56 years ?

When the date falls between the beginning of the Western year (1 January) and the end of the Indian Calendar year (Aso vad 30).

History of Indian Calendar system / Hindu calendar system :-

Backing Vedic literature one can easily acknowledge the existence of Science of time in Vedic Period that prevailed thousands of years before the Christian era.

The Rig Veda, cites months being lunar, but years luni-solar.

It mentioned about the constant relation between the solar year and its monthly lunar divisions. The lunar month is exactly 29 days 12 hours 44 minutes and 3 seconds long and twelve such months create a lunar year of 354 days 8 hours 48 minutes and 36 seconds. To match the lunar months with the solar year, the practice started of inserting extra months. Generally 60 solar months is equal to the 62 lunar months. So to accommodate this, an extra month named the Adhik Maas is added every after 30 months, roughly around every 2.5 years. This practice was prevalent even in Vedic times. An intercalary month mentioned in the Rig Veda proves that the month was added to preserve the correspondence between a whole solar year and the 12 lunations.

Two part lunar month

For calculation of length of a month, Indian calendar system uses the interval between two consecutive new moons (no moon) or full moons as a basis.

According to Panchang (which is sort of Hindu Almanac) every month has 30 tithis which are equally divided between 2 pakshas.

Name of Tithis of Shukla Paksha and Krishna Paksha

Once the Shukla (or sud) paksh, i.e. from sud 1 to (sud) Punam, is over it is followed by vad 1 to vad 14, but after vad 14 last tithi of the month is denoted as '(vad) 30' i.e., Amavasya.

Why sometimes we find that a tithi(Lunar day) is being 'omitted' or two consecutive days sharing the ‘same tithi’?

Tithis are calculated considering difference of the longitudinal angle between the position of the sun and the moon. Which lead to a situation wherein at the time of sunrise, the tithi may or may not have changed.

Name of Rutus (Seasons) as per Hindu Calendar

Entire year (Solar year) consisting of 12 months is formed combining 6 seasons each having approximately 2 months (Lunar months). Each of this season commence around the 21st date (± 2) of each even month of the Western calendar. Further a new day starts at sunrise and the night at sunset, whereas in Western calendar system day starts at midnight and night at evening or late afternoon.

Different New Year’s Day : Vivacious culture

There are several different days throughout the year are celebrated as New Year's Day in the different regions of India. It is determined by whether the lunar calendar is being followed or the solar calendar. Those regions which follow the Solar calendar, the new year falls in the month of Vaishakha (Hindu Solar New Year in Punjab, Northern and Central India) i.e., around 14th – 15th of April. Those following Lunar calendar consider the month of Chaitra (Hindu Lunar New Year in Andhra Pradesh, Telangana, Karnataka) i.e between March and April as the first month of the year. In Gujarat the new year is celebrated on the day after Diwali, which falls on Shukla Paksha Pratipada in the month of Kartik.

The Indian government and business enterprises uses the Gregorian calendar for administrative purposes. So obviously we can’t arrange our meetings and schedules in this era of Generation Z and Alpha as per Indian Dating System / Vikram Samvat since it’s mass is embedded with technology that is only maneuvering around Western / Gregorian calendar system. Festivals in India don’t follow the Gregorian calendar but the traditional local calendar. So in order to remain contiguous with the Traditional Vedic calendar system, it becomes crucial to have basic idea regarding how this system functions and understanding of various terminologies connected with it viz., Tithis, Shukla Paksha and Krishna Paksha etc. Our calendar looks everything from the different phases of the moon, the positions of stars, planets and identifies fortunate times and days to perform various activities like marriage, various sanskar or purchase of gold, vehicle or home etc.