The Hindu Calendar – Panchanga
The Hindu calendar, also called Panchanga, is an ancient time reckoning system used for, among other things, determining the dates of Hindu festivals. It is a lunisolar calendar with many regional variations.
One of the most striking features of the Hindu calendar system is its intricacy. It offers a multi-dimensional method of structuring time, combining information about lunar days, solar days, lunar months, solar months, the movements of the Sun and the Moon in relation to stellar constellations, and other astronomically defined time spans. This makes the Hindu calendar vastly more complex than the western calendar, which is built around only two basic units of time: solar days and solar years.
To complicate things even further, there is not one single Hindu calendar. Each country and region uses its own variant of the ancient system. The Indian National Calendar or Saka Calendar, the official standardized calendar of India since 1957, represents but one of many variations of the Hindu calendar. Still, there are some features that are common to all or most variants. These are presented below.
12 Lunar Months...
Months in the Hindu Calendar
|Solar (civil) Months
The Hindu calendar uses a lunisolar system, meaning that it takes into account the apparent movements of both the Moon and the Sun, as seen from Earth. It is primarily based on the length of a synodic lunar month. Each of the 12 lunar months in the calendar encompasses the time it takes the Moon to orbit the Earth in relation to the Sun.
Each lunar month is divided into 30 lunar days. These are further grouped into two fortnights with 15 days each: a “bright” fortnight that comprises the waxing half of the phases of the Moon and a “dark” fortnight that features a waning Moon.
...and 12 Solar Months
At the same time, the Hindu calendar tracks solar months, which are defined by and named after the zodiac signs the Sun traverses during different parts of the year, as seen from Earth. While the lunar months are commonly used to determine religious holidays and rituals, the solar time reckoning usually serves as the basis for civil purposes, so solar months are also referred to as civil months.
When Does the Year Begin?
In most regions, the year starts on the New Moon before the Sun enters the zodiac sign of Aries (Meṣa). This happens on or around the day of the March equinox, which marks the beginning of spring in the Northern Hemisphere.
Added or Omitted Months
Since 12 lunar months amount to only 354.367 days on average, a leap month is added about every three years. This synchronizes the calendar with the length of a sidereal year, which is the time it takes Earth to orbit the Sun in relation to fixed stars. An average sidereal year lasts about 365.256 days.
A month can either be added or omitted. An intercalary month, called Adhik Maas or Purushottam Maas, is added when a lunar month starts and ends before the Sun has moved to a new zodiac sign. In the rare case that the Sun traverses a whole zodiac sign during the course of a lunar month, the month is removed from the calendar. When this occurs, another month is repeated elsewhere in the year, so the year always has 12 or 13 months.
Lunar Days and Solar Days
Hindu time reckoning applies a similar correction mechanism to keep lunar days and solar days in sync. It defines a lunar day as the time span in which the Moon moves 12° in relation to the Sun—a 30th of the 360° it travels during a synodic lunar month. A solar or civil day is defined by the moment of sunrise.
If a lunar day starts and ends in the course of one solar day, a day is omitted in the calendar, so the date may jump from the 5th to the 7th of the month, for example. On the other hand, if a lunar day encompasses two sunrises, the day number is repeated. In that case, two consecutive days are assigned the same number.
Nakshatra, Yoga, and Karaṇa
The Hindu calendar also tracks various other astronomical time spans:
- Nakshatra: Also called lunar mansions, nakshatras are portions of the Moon's orbit around the Earth, each measuring 13° 20′. They are derived from Hindu astrology.
- Yoga: The yogas are portions of the combined longitudes of the Sun and the Moon, each measuring 13° 20′. Each yoga is associated with certain human qualities, deities, or other mythological figures, and each solar day is associated with the yoga reached at sunrise.
- Karaṇa: A karaṇa encompasses half a lunar day. As with yogas, each karaṇa is associated with certain qualities, and each solar day is associated with the karaṇa that is active at sunrise.
Hindu Festival Calendar
The dates of many, but not all, Hindu holidays are determined according to the lunisolar calendar. In most cases, the festivals coincide with the Full Moon or the New Moon, or they are celebrated on the day after the Moon phase. Holidays based on the Hindu calendar include Maha Shivaratri, Holi, Guru Purnima, Ganesh Chaturthi, and Diwali.
Although a holiday generally occurs on the same day in all regions, its date in the calendar can vary, depending on the variant of the Hindu calendar that is used. For example, a holiday may fall on the Full Moon at the beginning of a month in regions where the months start on the day of the Full Moon. However, in regions that use the New Moon variant of the Hindu calendar, the same day falls on the Full Moon in the middle of the previous month.
History and Background
The Hindu calendar was developed in ancient times by various scholars on the Indian subcontinent. The earliest mentions of Hindu time reckoning can be found in the Vedas, a body of sacred texts of Hinduism, some of which date back to around 1200 BCE.