PANCHANGA 2

 Indian Calendars

 

ABSTRACT

The Indian calendars are interesting, but very complicated. Indians use both solar and

lunisolar calendars. The solar calendars follow the sidereal year. The lunisolar calendars are of

two types; some have months that run from new Moon to new Moon, while some have months

that run from full Moon to full Moon. Leap months are a common feature of these lunisolar

calendars. In addition to leap months, the lunisolar calendars sometimes skip months. One lunar

month can sometimes overlap three solar months, so the lunar month corresponding to the

overlapped solar month is skipped. They also follow the Moon for the days, so sometimes they

skip or add days. They are probably the most complicated calendars currently used in the world.

There are also several regional variations. Specifically the two types of lunar calendars are used

in northern and southern India respectively. Another important highlight is that none of the

Indian calendars takes into account the precessional motion of the earth; therefore they have to

be adjusted to arrive at the correct results.

SOLAR CALENDARS

The solar year is the time period of the earth.s revolution around the sun. If instead of taking the

sun as a fixed body, we assume the earth to be fixed, then the sun will seem to be moving

around the earth. Therefore, the time taken for the sun to make a complete revolution of the

earth and come back to the same reference point in the sky will be the measure of a year. The

reference point to which the sun returns every year is fixed in two different ways, which yields

different results for the length of the year.

Sidereal or nirayana system

A fixed point on the ecliptic with reference to a background star.

Tropical or sayana system

Any of the two equinoxes or equinoctial points, which for calendarical and astronomical

purposes is normally taken to be the vernal or March equinotical point.

Effect of precession

Due to the precessional motion of the earth, under the tropical system the distance that the

sun has to travel is reduced to 360°-50..3 every year. And therefore the length of the tropical

  

Leap Year in Sidereal system

In a nirayana or sidereal year calendar when the months have a fixed number of days and a

normal year has 365 days, to compensate for the left over period of 0.256363 day, there will be

continuous leap years, including century years, at intervals of four years, also there will be

additional leap years added mathematically added at intervals of 157 years, this can be rounded

off to 160 years. This rounding up is probably so that these leap years will not coincide with the

usual leap years that are added every four years. If we take a scenario where 4AD was taken to

be a leap year, also 2AD was a specially added leap year. If we were to follow a 157 year

interval, in the third cycle we get a sum of 316 which is divisible by 4. So now the question is

does this leap year contain two leap days? However, if we follow a 160 year cycle, we do not

run into the problem.

In India the sidereal or nirayana system is followed by the traditional calendar. It follows the

calendarical principles laid down in the ancient astronomical treatise named as Surya Siddhanta.

The fixed initial point is the point on the ecliptic which is placed opposite the bright star Chaitra

(Spica . á Virgins) located close to the ecliptic. This fixed point is also the vernal equinoctial

point of the vernal equinox day of 285AD. Due to the precessional motion the fixed point in the

sky which was opposite to the star Chaitra has shifted considerably since 285AD (23°49. on 1ST

January 1997).

INDIAN SOLAR CALENDARS

There are twelve rasis or zodiacs in the sky. The ecliptic lies in the middle of this zodiac belt.

These twelve zodiacs divide the ecliptic into twelve equal arcs of 30°  each. In the tropical

system the start of these divisions is from the vernal equinoctial point, but in the sidereal system,

the start of the divisions is made from the earlier mentioned fixed point from which Mesha rasi

(Aries) starts.

The length of the months are based on the time taken by the sun to traverse the respective

rasis, which is the period covered from the time at which the sun enters the concerned rasi, to

the time it enters the next rasi. The moment at which the sun enters a rasi is known as a

Samakranti.

The samkranti however, may take place at any time of day or night. The day of the month of

the traditional calendar known as the savanna or panchang day starts with sunrise. Therefore,

depending on the time of the samkranti and the convention followed to determine the starting

day for the month, there are four different conventions for four different regions. The month

may commence on the same day as the samkranti, or on the following day, or sometimes in

some regions, the day after. Due to the regional variances, sometimes the same month has

different number of days in different regions. Also the same month in the same region may have

different number days in different years.

REGIONAL VARIATION IN INDIAN SOLAR CALENDARS

There are four different conventions for choosing the starting day1of the months followed in

different regions of India.

 

Orissa School

The solar month begins on the same day when the sun enters the concerned rasi. This

convention is followed in Orissa, Punjab and Haryana where solar calendars are used.

Tamil School

When the samkranti takes place before sunset, the month begins on the same day. If it takes

place after sunset, the month begins on the next day. Generally followed in Tamil Nadu.

Malyali School

The month begins on the same day if the samkranti happens before aparahna, i.e., before 3/5th

Of the time from sunrise to sunset. Otherwise, it begins on the next day. Generally followed in

Kerala.

Bengal School

When a samkranti takes place between sunrise and the following midnight, the solar month

begins on the next day, and when it begins after midnight, the month begins on the day

following the next day, that is, on the third day. This is the general rule, and in some special

circumstances, there are some deviations from this rule. Generally followed in Bengal, Assam

and Tripura

LUNISOLAR CALENDAR

The lunar month counted from new moon to new moon is known as amanta and lunar

calendar based on this month is called amanta calendar. When the month is counted from full

moon to full moon it is known as purnimanta and the respective calendar as purnimanta calendar.

As the lunar year is shorter than the solar year, and is kept adjusted to the latter by the

addition of intercalary months at intervals. The starting day of the lunar year will differ from

year to year and will oscillate between the days of March and April. This is because

Chaitra generally covers the period from 15th March to 13th April.

Amanta Lunisolar Calendar

The amanta calendar is also known as mukhyamana (mukhya meaning primary), especially

in the north, because even where purnimanta calendar is followed, the amanta calendar is used

to fix the dates of festivals.

The amanta lunar calendar starts from the Chaitra. The months of the amanta lunar calendar

are named after the solar months in which the new moon of the lunar month occurs.

The months are divided into two parts . Sukla paksha (bright half of the month), covering

the time period from new moon to the next full moon, and Krishna paksha (dark half of the

month), covering the period from full moon to the next new moon.

Tithi

Tithi is the time during which the moon gains successively 12º  or its integral multiples.

There are 30 tithis, of which 15 are Sukla paksha and 15 are Krishna paksha. Tithis are serially

numbered 1 to 15, and are suffixed .S. . Sukla (bright half of the month) or .K. . Krishna (dark

half of the month).

 

The days of the months of the lunar calendar are numbered in accordance with the serial

number of the Tithi prevailing at sunrise.

As the motion of the moon is not steady, the duration of a Tithi may vary from 19.98 hours to

26.78 hours. This sometimes results in a Tithi period covering two successive sunrises, or falling

between these, i.e. not covering any sunrise. When this happens there is a break in the counting

of tithis because one Tithi will be repeated and one will be omitted.

Adhika month

In the Indian lunisolar calendar the intercalary months are not added in a mechanical manner.

The Indian astronomers devised a method which uses the true positions of the sun and moon to

add the intercalary months. When two new moons occur within one solar month then two lunar

months occur with the same name based on the solar month. The first lunar month of the two is

prefixed with the title .Adhika. or .mala. and is considered as an intercalary month. The second

one starting from the next new moon is prefixed .suddha. and this latter month is considered to

be the true or normal month.

Under the above system intercalary months occur at an interval of 2 years 11 months, 2

years 10 months, or 2 years 4 months. The average time interval works out to be 2.7 years which

is the theoretical average time interval for occurrence of such months.

Kshaya month

It may happen that a lunar month will completely overlap any of the short three nirayana

solar months of Agrahayana, Pausha and Magha. In this case, no new moon will occur in that

overlapped solar month, and thus there will be no lunar month named after this solar month.

There would be a missing or .Kshaya. month in the lunar year. This might occur at intervals as

close as 19, 46, 65, 76, 122 and 141 years.

When such a Kshaya month occurs in a lunar year, there will always be two Adhika lunar

months in that period, one before and after the Kshaya lunar month. One of these two

Adhika months is treated as an intercalary month and other one as a true month.

Purnimanta Calendar

In this calendar the month covers the period from one full moon to the next. It is named after the

amanta month which occurs a fortnight later. Purnimanta lunar month begins a fortnight before

the initial new moon of the amanta lunar month, after which it is named; and ends in the middle

of that particular amanta month.

A logical deduction would show that while an amanta month can fall completely outside the

solar month it is named after, the purnimanta month would always cover at least half of the solar

month in question.

Other features like pakshas are similar to those of the amanta months.

Also noteable is the fact that the first month of the year (Chaitra or Vaisakha) and the year do

not start at the same time. The year starts in the middle of the lunar month chaitra, resulting in

 

counting the krishna paksha of chaitra in the previous year. The year starts with the begining of

sukla paksha of chaitra.

 

 

 

MATERIAL FOR BA PAERT1/ PAPER3