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All
measurements of time have historically depended on astronomical observations - the
day is measured from the rotation earth on its axis, the week approximates the changing
phases of the Moon, the month is measured from the revolution of the Moon around earth and
the year is measured from the revolution of earth around the Sun.
Unfortunately earth or moon do not complete their cycle in full no of
days. Moon's cycle is 29.53059 days and earth's orbit around sun takes 365.242196 days. So
12 months are short of a year, and 13 months are longer. In this lesson we describe here
the history and detailing of the commonly used Gregorian Calendar along with the different
lunar calendars used in India.
1. Gregorian Calendar : The Gregorian
Calendar was first
introduced by Julian Calendar. It was based on 365.25 days. The year was divided in twelve
months, of which eleven contained 30 or 31 days and the 12th had 28 days only. The first
month was March and the last month was February. July is named after Julius Caesar and
August after Augustus Caesar, both months being allocated the full 31 days, as belittled a
Caesar. The seventh month was September, the eight October, the ninth November the tenth
December, after the Latin Septem, Octo, Novem and Decem for seven, eight, nine & ten
respectively.
To account for quarter day, every fourth year the last month February
was a leap year. February contained 29 days. However this colander was fast by over 11
Minutes every year and by 1500 the error amounted to approximately 11 days. To correct the
calendar, Pope Gregory ordered that October 15,1582 should follow October 4. The new
Calendar also moved the beginning of the year from March 25 to January 1. February now did
not have a leap year in centuries unless perfectly divisible by 400. Thus came the present
Gregorian Calendar into existence.
According to the present Gregorian Calender average year is 365.2425 days which is more
than the actual by .000304 days, that is, 26 seconds. This can be accounted
for, if we again have February of 28 days after 3200 years. However, this is not
yet accounted in the Gregorian calendar.
Indian National
Calander: This is based on Sun - Starts when
Sayan Sun enters into Aries. It was recommended by the Calendar Reform Committee and
introduced by the Govt. of India from 22nd March 1957, corresponding to the 1st of
Chaitra, 1879 Saka Era. In this Calendar the no. of days assigned to each month and its
starting is as follows :
Month of Gregorian Date
Indian Calendar for 1st of the month
Chaitra (30 days March 22 (March 31 days in a 21 in a leap year)
Vaisakha 31 days April 21
Jyaistha 31 days May 22
Asadha 31 days June 22
Sravana 31 days July 23
Bhadra 31 days Aug 23
Asvina 30 days Sep 23
Kartika 30 days Oct 23
Agrahayana 30 days Nov 22
Pausa 30 days Dec 22
Magha 30 days Jan 21
Phalgun 30 days Feb 20
Lunar
Calendar : This is the most commonly used
calendar in India. This is based on the timing of new Moon. Depending upon Moon's transit over Sun
takes place in which sign, the month is named. When new moon is in Aries, the month is
Vaishakh, in Taurus it is Jyestha etc.
Lunar
calendar is of two kinds normally :
(i) Closing at full Moon i.e. Purnimanta
(ii) Closing at New Moon i.e. Amanta.
In Purnimanta the month starts 15 days before the new Moon & ends
on full Moon called Puranmasi meaning "month is complete." In Amanta month
starts after new moon. The months are named same as in Indian National Calendar
and they
start within 15 days before or after, of starting of months in Indian National
Calendar.
Since the speed of Moon is variable and it can cross over Sun at any
degree. New moon may sometimes occur twice in the same Rasi or may not occur at all in
some rasi. This gives formation of Adhik & Kshay Mah respectively. In case of Adhik
month; the two months are named as first and the other as second. Shukla Paksh of the
first and Krishna Paksh of the second are called the adhik month, which is normally
avoided in most muhurthas. In case of kshay month, one month is divided into two Pakshas
and each month is assigned one Paksh. The first month having Krishna Paksh is called Kshay
Mah and the other is termed normal Mah.
On the average year as 29.53 x 12 = 354.36 days, which is less by 11
days compared to earth's cycle. Thus in every three years there is an Adhik Mah to cover
the gap of these 11 days.
Kshay Mah occuse rarely. After or before Kshay Mah Adhik Mah occurs
invariably.
The start of month or day is taken from Sun rise. Because of variable
Moon. speed two tithis may fall between two sunrises and sometimes it may not fall even
once.
This gives rise to formation of Adhik and Kshay
tithis.
Solar
Calendar :
Like Lunar Calendar Solar Calendar
is based on
the movement of Sun. Sun's entry into Aries starts the month Vaisakh and also the new
year. The months are named same as in Indian National Calendar.
Though the moment of Sun's entry into a sign is the same all over
India, yet the commencement of the corresponding month for civil purposes is not
necessarily the same all over India, yet the commencement of the corresponding month for
civil purposes is not necessarily the same all over India. In Punjab &
Orissa the solar
month starts on the day of transit into next sign. Here day means one sunrise to
next-sunrise. In Bengal and Assam, if transit happens before midnight (45
Ghatis), the
solar month begins next day & when the transit occurs after 45 Ghatis, the month
begins a day after. In Tamil, when the fraction of the day at which transit occurs does
not exceed 30 Ghatis (Sunset), the solar month begins on the same day else next day. Since
the sun takes different times to transit a sign the month varies from 28 days to 31 days.
The lunar & solar
calendars are associated with various eras. Some
of the most commonly used are :
1. Vikram Era : 57 more than the A.D. year and extensively used
in Gujarat & all over northern India except Bengal. In Northern India year starts from
Chaitra Purima. It is also popularly known as "Malava Era" or simply
"Samvat".
In Gujarat Amanta month is taken and year starts from next day of
Kartika New Moon i.e. day of Diwali.
2. Saka Era : This is 78 less than A.D. year. This is also used
extensively in North India. Indian National Calendar uses this Saka. It is used both with
amanta & Purnimanta months as well as with solar calendar.
To
summarize year 1999 will have various Calendars beginning on the
following date:
1. Gregorian
Calendar : 1st Jan 99.
Different eras have following values :
i.
Gregorian
1999 A.D.
ii. Samvat
2056
iii. Saka
1921
iv. Kaliyuga Era. 5100
v. Fusli San
1407
vi. Kollam Era 1175
vii. Bengali San 1406
viii.Hejira
1420
2. National
Calendar : 22 March 99
3. Lunar Calendars :
Chaitradi : 18/3/99
Kartikadi : 10/10/99
4. Solar Calendars :
Bengal & Assam - 15/04/99
Punjab & Orissa - 14/04/99
South - 14/04/99
5. Kollam Era : A.D. year minus 824 is the Kollam Era. It is
used in Malabar, Cochin & Travancore. It starts with solar Virgo in North Malabar and
with Solar Leo in South Malabar.
6. Bengali San : Current A.D. year minus 593 gives Bangali San.
It starts with Sun entry into Aries.
7. Hejira (Muslim
Calender) : It is calculated by subtracting
579 from the current A.D. year. The monthly are based on Moon and are named as
Muharram,
Safer, Ravi-Ul-Avval, Ravi Ussani, Jamadi-Ul-avval, Jamadi Ussani, Rajjab,
Sawan, Ramjan, Savval, Jilked and Jilhej. Muharram the first months coincides with or starts from shukla
Paksh of Vaisakh. The month start normally from 2nd in Shukla Paksh when Moon is visible
in the sky after sun set. The day is counted from sunset to sunset. The only problem in
Muslim Calendar is that it can not be defined in advance since it is based on visibility
of Moon. If Moon is not visible on the day month has to start, it will be started from the
next day only when moon becomes clearly visible.
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