Hindu calendar
The
Hindu calendar used in ancient Vedic times has undergone many changes in the process of regionalization, and today there are several regional
Indian calendars, as well as an
Indian national calendar. Mostly, these are inherited from a system first enunciated in
Jyotish Vedanga (one of the six adjuncts to the
Vedas, 12th to 14th century BC), standardized in the
Surya Siddhanta (3rd century) and subsequently reformed by astronomers such as
Aryabhata (499),
Varahamihira (6th century), and
Bhaskara (12th century). There are differences and regional variations abound in these computations, but the following is a general overview.
The Hindu calendrical day starts with local sunrise. It is allotted five "properties", called
anga-s. They are:# the
tithi active at sunrise# the
vaasara or weekday# the
nakshatra in which the moon resides at sunrise# the
yoga active at sunrise# the
karana active at sunrise.Together these are called the
panchānga-s where
pancha means "five" in
Sanskrit. An explanation of the terms follows.
Tithi
The (anticlockwise) angular distance between the sun and moon as measured from the earth along the
ecliptic (circle on the sky in which the sun, moon and planets seem to move) can vary between 0° and 360°. This is divided into 30 parts. Each part
ends at 12°, 24° etc. The time spent by the moon in each of these parts (i.e. the time taken for the angular distance to increase in steps of 12° starting from 0°) is called one
tithi.
The month has two
paksha-s or fortnights. The first 15
tithi-s constitute the bright fortnight or
shukla paksha and the next 15
tithi-s constitute the dark fortnight or
krishna paksha.
tithi-s are indicated by their
paksha and ordinal number within the
paksha. The 15th
tithi of the bright fortnight (full moon) is called
pūrnimā and the 15th
tithi of the dark fortnight (new moon) is called
amāvāsyā.
The
tithi in which the moon is at the time of sunrise of a day is taken to be the
tithi for the day.
Vaasara
The weekdays are as usual seven. They are (starting from Sunday):# Ravi vāsara# Soma vāsara# Mangala vāsara# Budha vāsara# Guru vāsara# Shukra vāsara# Shani vāsaraThere are many other variations of these names, using other names of the celestial bodies of the Sun, Moon, Mars, Mercury, Jupiter, Venus and Saturn. The word
vāsara means "weekday". In common language, the word 'vaasara' is replaced by 'vaara', so Friday is 'Shukravaara' etc.
Nakshatra
The ecliptic is divided into 27
nakshatras, which are variously called lunar houses or
asterisms. These reflect the moon's cycle against the fixed stars, 27 days and 7¾ hours. Nakshatra computation appears to have been well known at the time of the
Rig Veda (2nd"1st millennium BC).
The starting point for this division is the point on the ecliptic directly opposite to the star
Spica called
Chitrā in Sanskrit. (Other slightly-different definitions exist.) It is called
Meshādi or the "start of
Aries". The ecliptic is divided into the
nakshatras eastwards starting from this point.
The
nakshatra-s with their corresponding regions of sky are given below, following [Basham]'s Appendix: Astronomy. As always, there are many versions with minor differences. The names on the right-hand column give roughly the correspondence of the
nakshatra-s to modern names of stars. Note that
nakshatra-s are (in this context) not just single stars but are segments on the ecliptic characterised by one or more stars. Hence you will find many stars mentioned for one
nakshatra.
| Ashvinī | β and γ Arietis | | Bharanī | 35, 39, and 41 Arietis |
| Krittikā | Pleiades |
| Rohinī | Aldebaran |
| Mrigashīrsha | λ, φ Orionis |
| Ārdrā | Betelgeuse |
| Punarvasu | Castor and Pollux |
| Pushya | γ, δ and θ Cancri |
| Āshleshā | δ, ε, η, ρ, and σ Hydrae |
| Maghā | Regulus |
| Pūrva Phalgunī | δ and θ Leonis |
| Uttara Phalgunī | Denebola |
| Hasta | α to ε Corvi |
| Chitrā | Spica |
| Svātī | Arcturus |
| Vishākhā | α, β, γ and ι Librae |
| Anurādhā | β, δ and π Scorpionis |
| Jyeshtha | α, σ, and τ Scorpionis |
| Mūla | ε, ζ, η, θ, ι, κ, λ, μ and ν Scorpionis |
| Pūrva Ashādhā | δ and ε Sagittarii |
| Uttara Ashādhā | ζ and σ Sagittarii |
| Shravana | α, β and γ Aquilae |
| Dhanishthā | α to δ Delphinis |
| Shatabhishaj | γ Aquarii |
| Pūrva Bhādrapada | α and β Pegasi |
| Uttara Bhādrapada | γ Pegasi and α Andromedae |
| Revatī | ζ Piscium |
An additional 28th intercalary nakshatra, Abhijit (alpha, epsilon and zeta Lyrae - Vega - between Uttarasharha and Sravana), is in between Uttarashada and Sravana. Last two (third and fourth) Padas of Uttrashada and first two (first and second) Padas of Sravana are considered to be Abhijith.
The
nakshatra in which the moon lies at the time of sunrise of a day is the
nakshatra for the day.
Yoga
First, the angular distance along the ecliptic of any object on the sky, measured from
Meshādi (as defined above) is called the longitude of that object. When the longitude of the sun and the longitude of the moon are added, they produce a value ranging from 0° to 360°. (Values greater than or equal to 360° must be reduced to less than 360° by subtracting 360°.) This is divided into 27 parts. Each part will now equal 800' (where ' is the symbol of the
arcminute which means 1/60 of a degree.) These parts are called the
yoga-s. They are labeled:
# Vishkambha# Prīti# Āyushmān# Saubhāgya# Shobhana# Atiganda# Sukarman# Dhriti# Shūla# Ganda# Vriddhi# Dhruva# Vyāghāta# Harshana# Vajra# Siddhi# Vyatīpāta# Varigha# Parigha# Shiva# Siddha# Sādhya# Shubha# Shukla# Brāhma# Māhendra# Vaidhriti
Again, minor variations may exist. The
yoga that is active during sunrise of a day is the
yoga for the day.
Karana
A
karana is half of a
tithi. To be precise, a
karana is the time required for the angular distance between the sun and the moon to increase in steps of 6° starting from 0°. (Compare with the definition of a tithi above.)
Since the
tithi-s are thirty in number, one would expect there to be sixty
karana-s. But there are only eleven. There are four "fixed"
karana-s and seven "repeating"
karana-s. The four "fixed"
karana-s are:
# Kimstughna# Shakuni# Chatushpād# Nāgava
The seven "repeating"
karana-s are:
# Bava# Bālava# Kaulava# Taitula# Garajā# Vanijā# Vishti (Bhadrā)
* Now the first half of the first
tithi (of the bright fortnight) is always
Kimstughna karana. Hence this
karana is "fixed".
* Next, the seven repeating
karana-s repeat eight times to cover the next 56 half-
tithi-s. Thus these are the "repeating"
karana-s.
* The three remaining half-
tithi-s take the remaining "fixed"
karana-s in order. Thus these are also "fixed".
* Thus one gets sixty
karana-s from eleven.
The
karana active during sunrise of a day is the
karana for the day.
Now that the days are defined, we shall speak of how the solar calendar reckons its months and year.
As has been previously noted, the sun is observed to travel along the ecliptic. The ecliptic is now divided into twelve parts called
rāshi-s, starting from the point of
Meshādi defined above and moving eastwards. The names of the rāshis correspond to those in the West, and may indicate a common Sumerian origin. Greek astronomical interchange, as in the
Romaka Siddhanta, also led to a degree of homogenization. This table lists the rāshis along with their zodiac equivalents:
The day on which the sun transits into each
rāshi before sunset is taken to be the first day of the month. In case the sun transits into a
rāshi after a sunset but before the next sunrise, then the next day is the first day of the month. (Minor variations on this definition exist.)
The days are then labeled 1, 2, 3…. till the first day of the next month.
Thus we get twelve months with varying lengths of 29 to 32 days. This variation in length occurs because the earth's orbit around the sun is an ellipse, but also because of some variability in the transit point falling before or after sunrise. The months are named by the
rāshi in which the sun travels in that month.
The new year day is the first day of the month of
Mesha. Currently, it occurs around
April 15 on the
Gregorian calendar.
This is the structure of the Hindu solar calendar.
When a new moon occurs before sunrise on a day, that day is said to be the first day of the lunar month. So it is evident that the end of the lunar month will coincide with a new moon. A lunar month has 29 or 30 days (according to the movement of the moon).
The
tithi at sunrise of a day is the only label of the day. There is no running day number from the first day to the last day of the month. This has some unique results, as explained below:
Sometimes two successive days have the same
tithi. In such a case, the latter is called an
adhika tithi where
adhika means "extra". Sometimes, one
tithi may never touch a sunrise, and hence no day will be labeled by that
tithi. It is then said to be a
tithi kshaya where
kshaya means "loss".
Naming lunar months
There are twelve lunar month names:
# Vaishākha# Jyaishtha# Āshādha# Shrāvana# Bhādrapada# Āshwina# Kārtika# Mārgashīrsha# Pausha# Māgha# Phālguna# ChaitraDetermining which name a lunar month takes is somewhat indirect. It is based on the
rāshi into which the
sun transits within a lunar month, i.e. before the new moon ending the month.
There are twelve
rāshi names, there are twelve lunar month names. When the sun transits into the
Mesha rāshi in a lunar month, then the name of the lunar month is
Chaitra. When the sun transits into
Vrishabha, then the lunar month is
Vaishākha. So on.
The
Sanskrit grammatical derivation of the lunar month names
Chaitra etc is: the (lunar) month which has its central full moon occurring at or near the
nakshatra Chitrā is called
Chaitra. Similarly, for the
nakshatra-s
Vishākhā,
Jyeshthā,
(Pūrva) Ashādhā,
Shravana,
Bhādrapada,
Ashvinī (old name
Ashvayuj),
Krittikā,
Mrigashīrsha,
Pushya,
Maghā and
(Pūrva/Uttara) Phalgunī the names
Vaishākha etc are derived.
The lunar months are split into two pakshas of 15 days. The waxing paksha is called shuklapaksha,
light half, and the waning paksha the krishnapaksha,
dark half. There are two different systems for making the lunar calendar:
amanta or
mukhya mana system - a month begins with a new moon, mostly followed in the southern states
purnimanta or
gauna mana system - a month begins with a full moon, followed more in the North.
Extra months
When the sun does not at all transit into any
rāshi but simply keeps moving within a
rāshi in a lunar month (i.e. before a new moon), then that lunar month will be named according to the first upcoming transit. It will also take the epithet of
adhika or "extra". For example, if a lunar month elapsed without a solar transit and the next transit is into
Mesha, then this month without transit is labeled
adhika Chaitra. The next month will be labeled according to its transit as usual and will get the epithet
nija ("original") or
shuddha ("clean"). [Note that an
adhika māsa (month) is the first of two whereas an
adhika tithi is the second of two.]
An
adhika māsa occurs once every two or three years (meaning, with a gap of one or two years without
adhika māsa-s).
Lost months
If the sun transits into
two rāshi-s within a lunar month, then the month will have to be labeled by both transits and will take the epithet
kshaya or "loss". There is considered to be a "loss" because: if the sun had transited into only one
raashi in a lunar month as is usual, there would have been two separate months labeled by the two transits in question; but now there is only one month labeled by both transits!
For example, if the sun transits into
Mesha and
Vrishabha in a lunar month, then it will be called
Chaitra-Vaishaakha kshaya. There will be no separate months labeled
Chaitra and
Vaishākha.
A
kshaya māsa occurs very rarely. Known gaps between occurrence of
kshaya māsa-s are 19 and 141 years. The last was in 1983. Jan-15 through Feb-12 were
Pausha-Māgha kshaya. Feb-13 onwards was
(adhika) Phālguna.
Special Case:If there is no solar transit in one lunar month but there are two transits in the next lunar month,
* the first month will be labeled by the first transit of the second month (as usual) and take the epithet
adhika and
* the next month will be labeled by both its transits as is usual for a
kshaya māsa.
This is a very very rare occurrence. The last was in 1315. Oct-08 to Nov-05 were
adhika Kārtika. Nov-06 to Dec-05 were
Kārtika-Māgashīrsha kshaya. Dec-06 onwards was
Pausha.
Religious observances in case of extra and lost months
Among normal months,
adhika months, and
kshaya months, the earlier are considered "better" for religious purposes. That means, if a festival should fall on the 10th
tithi of the
Āshvayuja month (this is called
Vijayadashamī) and there are two
Āshvayuja months caused by the existence of an
adhika Āshvayuja, the first
adhika month will not see the festival, and the festival will be observed only in the second
nija month. However, if the second month is
āshvayuja kshaya then the festival will be observed in the first
adhika month itself.
When two months are rolled into one in the case of a
kshaya māsa, the festivals of both months will also be rolled into this
kshaya māsa. For example, the festival of
Mahāshivarātri which is to be observed on the fourteenth
tithi of the
Māgha krishna paksha was, in 1983, observed on the corresponding
tithi of
Pausha-Māgha kshaya krishna paksha, since in that year,
Pausha and
Māgha were rolled into one, as we mentioned above.
The new year day is the first day of the
shukla paksha of
Chaitra. In the case of
adhika or
kshaya months relating to
Chaitra, the aforementioned religious rules apply giving rise to the following results:
* If an
adhika Chaitra is followed by a
nija Chaitra, the new year starts with the
nija Chaitra.
* If an
adhika Chaitra is followed by a
Chaitra-Vaishākha kshaya, the new year starts with the
adhika Chaitra.
* If a
Chaitra-Vaishākha kshaya occurs with no
adhika Chaitra before it, then it starts the new year.
* If a
Phālguna-Chaitra kshaya occurs, it starts the new year.
There is another kind of lunisolar calendar which differs from the former in the way the months are named. This section describes the differences involved, and may be skipped if the article is already too complicated for the reader. It is only included for completeness.
When a full moon (instead of new moon) occurs before sunrise on a day, that day is said to be the first day of the lunar month. In this case, the end of the lunar month will coincide with a full moon. This is called the
pūrnimānta māna or "full-moon-ending reckoning", as against the
amānta māna or "new-moon-ending reckoning" used before.
This definition leads to a lot of complications:
* The first
paksha of the month will be
krishna and the second will be
shukla.
* The new year is still on the first day of the
Chaitra shukla paksha. The next
paksha-s will be the
Vaishākha krishna,
Vaishākha shukla,
Jyaishtha krishna and so on, till
Phālguna krishna,
Phālguna shukla and
Chaitra krishna, which is now the last
paksha of the year.
* The
shukla paksha of a given month, say
Chaitra, comprises of the same actual days in both systems, as can be deduces from a careful analysis of the rules. However, the
Chaitra krishna paksha-s defined by the two systems will be on different days, since the
Chaitra krishna paksha precedes the
Chaitra shukla paksha is the
pūrnimānta system but follows it in the
amānta system.
* Though the regular months are defined by the full moon, the
adhika and
kshaya lunar months are still defined by the new moon. That is, even if the
pūrnimānta system is followed,
adhika or
kshaya months will start with the first sunrise after the new moon, and end with the new moon.
* The
adhika month will therefore get sandwiched between the two
paksha-s of the
nija months. For example, a
Shrāvana adhika māsa will be inserted as follows:
*#
nija Shrāvana krishna paksha*#
adhika Shrāvana shukla paksha*#
adhika Shrāvana krishna paksha and
*#
nija Shrāvana shukla pakshaafter which
Bhādrapada krishna paksha will come as usual.
* If there is an
adhika Chaitra, then it will follow the
(nija) Chaitra krishna paksha at the end of the year. Only with the
nija Chaitra shukla paksha will the new year start. The only exception is when it is followed by a
kshaya, and that will be mentioned later.
* The
kshaya month is more complicated. If in the
amānta system there is a
Pausha-Māgha kshaya, then in the
pūrnimānta system there will be the following
paksha-s:
*#
Pausha krishna paksha*#
Pausha-Maagha kshaya shukla paksha*#
Maagha-Phaalguna kshaya krishna paksha and a
*#
Phālguna shukla paksha.
* The special
kshaya case where an
adhika māsa precedes a
kshaya māsa gets even more convoluted. First, we should remember that the
Āshvayuja shukla paksha is the same in both the systems. After this come the following
paksha-s:
*#
nija Kārtika krishna paksha*#
adhika Kārtika shukla paksha*#
adhika Kārtika krishna paksha*#
Kārtika-Māgashīrsha kshaya shukla paksha*#
Māgashīrsha-Pausha kshaya krishna paksha *#
Pausha shukla pakshafollowed by the
Māgha krishna paksha etc as usual.
* The considerations for the new year are:
*# If there is a
Chaitra-Vaishākha kshaya shukla paksha:
*## if an
adhika Chaitra precedes it, then the
adhika Chaitra shukla paksha starts the new year
*## if not, the
kshaya shukla paksha starts the new year
*# If there is a
Phālguna-Chaitra kshaya shukla paksha then it starts the new year
It must be noted, however, that none of these above complications cause a change in the day of religious observances. Since only the name of the
krishna paksha-s of the months will change in the two systems, festivals which fall on the
krishna paksha will be defined by the appropriate changed name. That is, the
Mahāshivarātri, defined in the
amānta māna to be observed on the fourteenth of the
Māgha krishna paksha will now (in the
pūrnimānta māna) be defined by the
Phālguna krishna paksha.
A
lunisolar calendar is always a calendar based on the moon's celestial motion, which in a way keeps itself close to a
solar calendar based on the sun's (apparent) celestial motion. That is, the lunisolar calendar's new year is to kept always close (within certain limits) to a solar calendar's new year.
Since the Hindu lunar month names are based on solar transits, and the month of
Chaitra will, as defined above, always be close to the solar month of
Mesha, the Hindu lunisolar calendar will always keep in track with the Hindu solar calendar.
The epoch (starting point or first day of the first year) of the current era of Hindu calendar (both solar and lunisolar) is
BCE 3102 January 23 on the
proleptic Gregorian calendar (i.e. the
Gregorian calendar extended back in time before its promulgation from
1582 October 15). Both the solar and lunisolar calendars started on this date. After that, each year is labeled by the number of years
elapsed since the epoch.
This is a unique feature of the Hindu calendar. All other systems use the current ordinal number of the year as the year label. But just as a person's true age is measured by the number of years that have elapsed starting from the date of the person's birth, the Hindu calendar measures the number of years elapsed.
As of May 18, 2005, 5106 years had elapsed in the Hindu calendar, so this is the 5107
th Hindu calendar year. Note that the lunisolar calendar year will usually start earlier than the solar calendar year.
Other systems of numbering the Hindu years can be read about at the
Samvat article.
Apart from the numbering system outlined above, there is also a cycle of 60 calendar year names, which started at the first year (at elapsed years zero) and runs continuously:
# Prabhava# Vibhava# Shukla# Pramoda# Prajāpati# Āngirasa# Shrīmukha# Bhāva# Yuvan# Dhātri# Īshvara# Bahudhānya# Pramāthin# Vikrama# Vrisha# Chitrabhānu# Svabhānu# Tārana# Pārthiva# Vyaya (the current Hindu year 2006-2007 CE carries this name)# Sarvajit# Sarvadhārin# Virodhin# Vikrita# Khara# Nandana# Vijaya# Jaya# Manmatha# Durmukha# Hemalambin# Vilambin# Vikārin# Shārvari# Plava# Shubhakrit# Shobhana# Krodhin# Vishvāvasu# Parābhava# Plavanga# Kīlaka# Saumya# Sādhārana# Virodhikrit# Paritāpin# Pramādin# Ānanda# Rākshasa# Anala# Pingala# Kālayukti# Siddhārthin# Raudra# Durmati# Dundubhi# Rudhirodgārin# Raktāksha# Krodhana# Kshaya
The Hindu tradition speaks of four eras or ages, of which we are currently in the last. The four are:
#
Krita Yuga or
Satya Yuga#
Tretā Yuga#
Dvāpara Yuga#
Kali YugaThey are often translated into English as the golden, silver, bronze and iron ages. (
Yuga means era or age.) . The ages see a gradual decline of
dharma, wisdom, knowledge, intellectual capability, life span and emotional and physical strength. The epoch provided above is the start of the
Kali Yuga. The
Kali Yuga is 432,000 years long. The
Dvāpara,
Tretā and
Krita (Satya) Yuga-s are two, three and four times the length of the
Kali Yuga respectively. Thus they together constitute 4,320,000 years. This is called a
Chaturyuga.
A thousand and a thousand (i.e. two thousand)
chaturyuga-s are said to be one day and night of the creator
Brahmā. He (the creator) lives for 100 years of 360 such days and at the end, he is said to dissolve, along with his entire Creation, into the Eternal Soul or
Paramātman.
A different view of the timespan of a yuga is given by Swami
Sri Yukteswar Giri, the
guru of
Paramahansa Yogananda. This is detailed in his book,
The Holy Science. According to this view, the chaturyuga spans a much lower timespan, on the order of thousands of years, and moves cyclically. According to calculations given in the book, the most recent yuga change was in 1800, when the Earth passed from Kali Yuga to Dvāpara Yuga. We are in an ascending spiral right now, and will pass into the Tretā Yuga in a few centuries. According to the book, the quality of human intellect depends on the distance of the
Sun from the galactic core and other powerful stars. In the book, the core of the galaxy is called
Vishnunābhi, or the navel of
Vishnu. The closer the Sun is to it, the more energy the
Solar System receives, and the greater is the level of human spiritual and overall development.
The Hindu Calendar descends from the Vedic times. There are many references to calendrics in the
Vedas. The Vedānga (adjunct to Veda) called Jyautisha (literally, "celestial body study") prescribed all the aspects of the Hindu calendars. After the Vedic period, there were many scholars such as
Āryabhata (5th century),
Varāhamihira (6th century) and Bhāskara (12th century) who were experts in Jyautisha and contributed to the development of the Hindu Calendar.
The most widely used authoritative text for the Hindu Calendars in the
Sūrya Siddhānta, a text of uncertain age, though some place it at 10th century.
The traditional Vedic calendar used to start with the month of agrahayan (agra=first + ayan = travel of the sun, equinox) or Mārgashirshe. This is the month where the Sun crosses the equator, i.e. the
vernal equinox. This month was called mārgashirshe after the fifth nakshatra (around lambda orionis). Due to the
precession of the earth's axis, the vernal equinox is now in Pisces, and corresponds to the month of chaitra. This shift over the years is what has led to various calendar reforms in different regions to assert different months as the start month for the year. Thus, some calendars (e.g. Vikram) start with Chaitra, which is the present-day month of the vernal equinox, as the first month. Others may start with Vaisakha (e.g.
Bangabda). The shift in the vernal equinox by nearly four months from agrahaayana to chaitra in sidereal terms seems to indicate that the original naming conventions may date to the fourth or fifth millennium BC, since the period of precession in the earth's axis is about 25,800 years.
The Indian Calendar Reform Committee, appointed in 1952 (shortly after Indian independence), identified more than thirty well-developed calendars, all variants of the
Surya Siddhanta calendar outlined here, in systematic use across different parts of India. These include the widespread
Vikrama and
Shalivahana calendars and regional variations thereof. The
Tamil calendar, an entirely different solar calendar, is used in
Tamil Nadu and
Kerala.
Vikrama and Shalivahana calendars
The two calendars most widely used in India today are the
Vikrama calendar followed in
North India and the
Shalivahana or
Saka calendar which is followed in
South India and
Maharashtra.
Both the
Vikrama and the
Shalivahana eras are lunisolar calendars, and feature annual cycles of twelve lunar months, each month divided into two phases: the 'bright half' (
shukla) and the 'dark half' (
bahula); these corrospond respectively to the periods of the 'waxing' and the 'waning' of the moon. Thus, the period beginning from the first day after the
new moon and ending on the
full moon day constitutes the
shukla paksha or 'bright half' of the month; the period beginning from the day after the full moon until and including the next new moon day constitutes the
bahula paksha or 'dark half' of the month.
The names of the 12 months, as also their sequence, are the same in both calendars; however, the new year is celebrated at separate points during the year and the "year zero" for the two calendars is different. In the Vikrama calendar, the zero year corrosponds to 56 BC, while in the Shalivahana calendar, it corrosponds to 78 AD. The Vikrama calendar begins with the month of
Kartika (Oct/Nov) and the
Deepavali festival marks the new year. The Shalivahana calendar begins with the month of
Chaitra (March/April) and the
Ugadi/
Gudi Padwa festivals mark the new year.
Another little-known difference between the two calendars exists: while each month in the
Vikrama calendar begins with the 'dark half' and is followed by the 'bright half', the opposite obtains in the
Shalivahana calendar. Thus, each month of the
Vikrama calendar ends with the full moon and the new month begins on the day after that, while the no-moon day brings each month of the
Shalivahana calendar to a close.
National calendars in south Asia
A variant of the
Shalivahana Calendar was reformed and standardized as the Indian National calendar in 1957. This official calendar follows the
Shalivahana calendar in beginning from the month of
Chaitra and counting years with 78 AD being
year zero. It features a constant number of days in every month (with leap years).
The Bengal Calendar,
Bangabda (introduced 1584), is widely used in eastern India. A reformation of this calendar was introduced in present-day
Bangladesh in 1966, with constant days in each month and a leap year system; this serves as the national calendar for
Bangladesh.
Nepal follows the Vikram calendar. The same month names and roughly the same periods apply to a number of
Buddhist calendars in
Sri Lanka,
Tibet and other areas.
Correspondence between calendars
As an indicator of this variation, 'Whitaker Almanac' reports that the Gregorian year 2000 AD corresponds, respectively with:#Year 5101 in the Kaliyuga calendar;#Year 2544 in the Buddha Nirvana calendar;#Year 2057 in the Vikram Samvat calendar;#Year 1922 in the Saka calendar;#Year 1921 (shown in terms of 5-yearly cycles) of the Vedanga Jyotisa calendar;#Year 1407 in the Bengali San calendar;#Year 1176 in the Kolla Varsham calendar.
* Reingold and Dershowitz,
Calendrical Calculations, Millennium Edition, Cambridge University Press, latest 2nd edition 3rd printing released November 2004. ISBN 0-521-77752-6
* A.L. Basham,
The Wonder that was India, Appendix II: "Astronomy", Macmillan, 1954. Rupa and Co, Calcutta, reprint.
* S. Balachandra Rao,
Indian Astronomy: An Introduction, Universities Press, Hyderabad, 2000.
* The majority of the text above was based from the pure astronomical definitions at
Panchangam in English,
Hindu Solar Calendar and
Hindu Lunar Calendar.
*
Detailed Daily Indian Panchang Online*
Online Panchanga describing all the five limbs*
Indian Calendar at Webexhibits.org*
Google Hindu Calendar*
Panchangam.com - Online Hindu Vedic Calendar*
Some facts on the Hindu Calendar by Pandit Sanjay Rath*
Vedic Calendar Program (freeware) For any modern year, anywhere in the world, tells when each tithi, each naksatra, and each lunar month occurs, and the dates for various festivals (especially Gaudiya Vaishnava). Also calculates birthdays. — Useful generally only for ISKCON adherents or North Indian Vaishnava traditions.
*
India through its calendars by Amartya Sen*
Comparing the Surya Siddhanta and the Astronomical Ephemeris by Daphne Chia (pdf, 404KB)
*
Indian Calendars by Akhil Doegar and Akshay Prasad (pdf, 804KB)
*
Indian Calendars by Leow Choon Lian (pdf, 1.22MB)
*
Panchanga-Tantra: The Magic of the Indian Calendar System by Regulagedda Akshay (pdf, 1.97MB)
*
Online Hindu Calendar*
Official calendar of Nepal Bikram Sambat 2063 *
Malayalam Calendar (Kolla Varsham) showing the day, dates, janma nakshatram and important events of the past 67 years.
