Surya Sankranti: Solar Calendar

The Solar Calendar
The Sun in the 12 signs of the Zodiac........Indian solar, lunar and lunisolar almanacs


India's numerous calendars count the days by the sun, the moon, a combination of the two, or by the Indian Zodiac of rashis, and beginning from several different Eras.
Calendars can be confusing: solar, lunar, lunisolar, zodiacal, weekly, epochal, fiscal… The very numerous and diverse people of India use around 30 calendars, depending on regional differences and religious, agricultural and astrological purposes. Astronomical and astrological information can be read off panchangams or panchangs, or printed calendars.

In the solar calendar, the beginning of each month is determined by the entry of the sun into one of the twelve “rashis” or signs of the Indian zodiac, which corresponds to the Western Zodiac (it has been speculated that the Western and the Indian zodiacs have a common Sumerian origin). This makes for 12 solar months, between 29 to 32 days in length, each named after the rashi the sun is traveling in during that month:

Mesha (April/May) = Aries
Vrushabha (May/June) = Taurus
Mithuna (June/July) = Gemini
Karka (July/Aug) = Cancer
Simha (Aug./Sept) = Leo
Kanya (Sept./Oct) = Virgo
Tula (Oct/Nov) = Libra
Vrushchika (Nov/Dec) = Scorpius
Dhanu (Dec/Jan) = Saggitarius
Makara (Jan/Feb) = Capricornus
Kumbha (Feb/Mar) = Aquarius
Meena (Mar/Apr) = Pisces

A lunar month can run from new moon to new moon, culminating with the Full Moon or Purnima, as in Southern India. In North India, however, months may begin with the full moon. The traditional names of the lunar months were adopted in the Indian national calendar, which was introduced in 1957. That more uniform calendar, however, is lunisolar, making each month count 30 or 31 days:

Chaitra (Chetra, Caitra, Chithirai): begins 22 March (21 March in a leap year)
Vaisakha: 21 April
Jyaistha: 22 May
Asadha: 22 June
Sravana: 23 July
Bhadra: 23 August
Asvina: 23 September
Kartika: 23 October
Margashirsh (Agrahayana): 22 November
Pausa: 22 December
Magha: 21 January
Phalguna: 20 February

When precisely a month begins is dependent on many variable, often intricate rules. There are also many different “Year 0”s from which the chronologies start counting. The Indian national calendar counts the years in the Saka Era, which is the reference for most Sanskrit astronomical works after 500 AD. Year 0 of the Saka Era corresponds to 78 AD, so the official New Year’s Day (22 March 2007) jumpstarts year 2064. But other calendars, many of which are far more popular, count from other Eras.

Needless to say, this makes for a lot of different Indian New Years and New Year’s Days!