We have already discussed the astronomical aspect of Hindu Calendar system-Shaka and Vikarmi Samvat. Let us have a brief idea of the historical background and essence of the same.
Shaka(Customary): Shaka era was introduced by King Kanishka of Kushan dynasty in the year 78 AD as Shaka 0. It is said that the era was already in existence since 122 BC as started by some Shaka king before the empire expanded into Indian subcontinent. Shakas were a stream of noble migrant tribe also called Scythians from western Asia/Iran. King Kanishka started the calendar afresh after certain corrections. According to another view it has nothing to do with Shaka rulers. Shaka is Sanskrit word. As already described it is Luni-sidereal calendar system. The year starts on 13th April ( 12 to 14th April) when Sun enters into Aries sign. It is known as Vaishakah 1. The months are named in accordance with the name of the Astreism in which full moon falls in that month, though with a little different pronunciation/accent, e.g. Vaishaka corresponds to asterism Vishaka. However in different parts of India there is a little difference in the convention followed regarding the beginning of year. We are referring to convention followed in Northern India. The length of the year is fixed as 365.265 days as an average- 365 days in normal years and 366 in leap years. Days are counted from Sunrise to Sunrise. For religious purpose Months begin on the day of transit of Sun from one Rashi( which is called Sign in tropical system) to next sign, starting from sidereal Aries (Mesha). For Civil purpose it may span across 2 days around the actual event. The months begin with dark fortnight. The length of the month varies from 29 to 32 days depending upon astronomical length based on Sun transit from one sign to another sign. There are different conventions in this respect too because the transit may take place anytime in 24 hours (i.e. before midnight, after midnight, before midday, after midday) but the day begins at Sunrise.
Shaka(official): After independence, of India, it was argued that Shaka was originally tropical in nature so a new system of Shaka year was introduced. The beginning of the year is counted from next day to vernal equinox day, 22 March, and 21 March in leap years. So this day is counted as Chaitra 1, and is taken as the beginning of the official year. Chaitra was originally 12th month (starting from 13th March) in Customary/sidereal Shaka. The length of the year is tropical (365.24 days). On March 22, 1957 this Luni-tropical calendar was accepted by Govt of India as official Calendar. The date was taken as Shaka 1879 in 23 days advance of the customary/sidereal Shaka 1879. Rest counting of month and their name is same as it was in sidereal Shaka. But for religious purposes Customary Shaka is still in vogue. The sequence and name of the months in Customary Shaka are as follows-Vaishaka, Jaishtha, Asharra, Shraban, Bhado, Ashwin, Kartika, Agrahanya, Paush, Magha, Falguna,Chaitra)
Vikarmi Samvat: This era was started in around 57 BC by the Malba tribes from an area around present-day Punjab. However practically it came in vogue in around 1BC. It was later on fixed by Chandergupta II (also known as Vikarmaditya) of Gupta dynasty in around 395 AD. Since then it is known as Vikarmi Smavat (Samvat for year). This is Luni-solar system. There are 12 months in year but each month consists of fixed 30 Tithis (Lunar day or Tithi is the time taken by moon to complete one rotation round the earth which varies from day to day. Solar day spans from sunrise to sunrise which is always 24 hours). Months are named in accordance with the Asterism occupied by the near full-moon of the month, same as in Shaka. All months begin as it is, as it was in customary Shaka, from the first day of dark fortnight with the same naming system. But the year starts from the Tithi current at sunrise time of the 1st day of the lighted fortnight of Chaitra which may fall anytime from 14th March to 14 April because of the difference in number of solar days and lunar days in a year. So, half of the Chaitra(dark fortnight) always falls in previous year of this calendar system.. Further the issue is that Lunar days (Tithis) does not keep pace with Solar days. In fact 1 Tithi(from beginning to end) may span across two sunrises hence two solar days, and 2 Tithis(beginning to beginning) may cover only one solar day. Meaning thereby in almanac accordingly there may be two rows for 1 Titihi but two solar days, and there may be two rows for 1 solar day but two Tithis. The counting of Tithi starts from 1 to 15 for each fortnight (dark and lighted) separately though overall there are 30 Tithis in a month. So finally there are 360 lunar days and 354 solar days in a year of this system. So, each year begins with different day of the Gregorian calendar system, generally falling 10 days behind of the beginning day of the previous year of this system. For example if this year began with 27th March then next year may begin with 16 March. Hence at the end of around 32/33 solar months, 1 extra month is accumulated which is added as an intercalary month. For example it can be said there will be two Jyeshta this year. So in that particular year there are 390 lunar days in a year of this system. Further the cycle repeats same way as it was 32/33 months ago. It is to be reminded ( as discussed at length in PART V of this article ) that Sidereal Shaka and Vikarmi Samvat are two different issues, though in both the systems the naming of months and the sequence is same. Shaka year is Solar/Sidereal consisting of 365/366 days while Samvat is Lunar consisting of 354 days. So the beginning of Sidereal year is fixed(13/14th April as Vaishakh 1 with Sun’s transit into Aries Rashi of sidereal zodiac) but beginning of Samvat(as Chaitra 1 of Lighted fortnight preceded by dark fortnight, or to say Chaitra 16th of the month of Chaitra) is not fixed as per Gregorian calendar. Meaning thereby Chaitra of the two systems are completely different issues. Further official Shaka year is Solar/Tropical with Chaitra 1 falling on on 22/23 March is fixed but falls on different days as per Samvat. All these issues are reflected in each row of the Indian almanac.
Islamic calendar system follows what is called Hijri era started on 622 AD by Mohammad the Prophet. This is followed By Muslims all over world. Hijrat(Arabian/Urdu word) stands for the flight of Mohammad from Mecca to Madina. Mecca was his hometown. There are different opinions regarding the exact date but it was Friday. The dates suggested are July 16, March 19(vernal equinox) and September 20. Initially it was Luni-solar Calendar system, meaning thereby to adjust Solar year with Lunar year an extra last month (called Jelhaj) as an intercalary month was accumulated one of which was not counted. But this was causing some confusion and hardship to the pilgrims of Mecca because they have to unnecessarily stay and to wait for one month more at the pilgrim site when intercalary month used to come into picture. So prophet decided to drop this system in favor of purely Lunar system. The day in this system begins with Sunset. A month begins with first visible crescent of moon as seen in the second lunar day of lighted fortnight. Normally like in other Lunar system the year consists of 360 lunar days or 354.36 solar days. So the beginning of year is receding permanently back in round robin fashion. In this system the concept of leap year is a little different. A group of 30 years is taken in account. It contains 19 normal years of 354 days, and remaining 11 years of 355 days called leap years. This came to be 354.355 solar days as an average. But beginning of year is also adjusted on the basis of visual observation of moon so the resulting error does not matter. Years divided by 30 leaving remainders 2,5,7,10,13,16,18,20,24,26,29 are called leap years. The names of the months and corresponding days are as follows-Maharram(30), Shafar(29),Rabialaul(30),Rabias-sani(29), Jamadailul(30), Rajab(30), Shaban(29), Ramjan(30), Shawal(29), Jelked(30) and Jelhajj(29).
Further in India the Mughul emperor Akbar started several eras for different regions in keeping with both Hijri era and Hindu tradition followed by local people. Some of those are as follows.
1)Fusli era-There are three Fusli eras according to the region it was assigned to, namely-Hindi(North) Fusli, Decan(South) Fusli and Mumbai Fusli .
Hindi Fusli was started in 1584 AD but taking the beginning from 593 AD, which perhaps coincided around with date of birth of Prophet. So 1584 AD came to be known as 991 Fusli. This is a luni-solar system. The year starts from 1st lunar day, current at Sunrise, of the dark fortnight in the month of September, as called Aswina in Shaka.
Decan Fusli was started in 1586 AD for South India, and the current year was taken as 991 Fusli, starting from 595 AD. The year is purely solar and begins on 1st July with sun transit into Pushya (Delta Cancri).
Mumbai Fusli is same as Deccan Fusli but the year begins on Sun transit into Mrigshirsha(Orion).
2) Bengali era or Sana Era- For the people of Bengal as started from 1556 AD, back dated from 593 AD as 963 Sana. This is Luni-solar like sidereal Shaka but for beginning of the year. This starts with Sun’s transit into Taurus.
3) Bilayti era- For the people of adjacent state of Orissa. It is almost same as Sana era but for the convention followed for beginning of year. This starts with Sun’s transit into Virgo in the month of September (Ashwina) )
4) Amli era-This was also for Orissa. This was started in the year 1584 AD again taking 593 as beging of the era. The calendar is Luni-solar starting with Sun’s transit into Leo(Vadra) in the month of August on 12th day of the lighted fortnight current at sunrise.
To be followed by an Appendix on Local, Standard and Sidereal time……..