Seasons from the Sun
Kamal Lodaya, Bengaluru

This is a series about calendar makers from history. The last issue's article discussed how the Moon's motion among the stars every day was recorded by 27 {nakshatras}, 12 of these gave names to the months in the year.

Stars at night calculate the Sun in the day
As seen from Earth, the Sun traces a circle around us against the stars in its yearly path in 365.2422 days. This is called a {tropical} or {seasonal} year, for example, from {spring equinox} this year (March 21) to spring equinox next year, when Sun-Earth-stars are in the same positions. Or if you like, from your birthday this year to your birthday the next.

The Sun's path in the sky is divided into 12 {solar rashis} or signs of the Zodiac. These are specific constellations (groups of stars) in the sky. Each has many stars. For example in March and April the stars behind the Sun are from the Meena (Pisces) and Mesha (Aries) rashis. 

Since the Sun is so bright the stars in these rashis cannot be seen then. But the Sun and Moon's paths form nearly the same plane, so these rashis overlap with the nakshatras. The 12 rashis have 27 nakshatras, each rashi has 2 or 3 nakshatras. Which stars lie behind the Sun can be calculated by seeing at midnight 
the nakshatra {opposite} to the Sun in the sky.

Solar rashis are very old markers for dividing the Sun's path. They were known to the Babylonians of today's Iraq in 1800 BCE. The Babylonians also developed astrological ideas about the supposed effect of stars on humans. Babylonian almanacs are found which list good and bad days of a year, with advice on what to do for every day.

The names of some rashis are very old but they seem to have been finalized in Persia (Iran) in the 5th century BCE. In India the oldest appearance of rashis is in Tamil {Sangam} literature in the 3rd century CE. They are not found in the {Mahabharata} (which has nakshatras), completed around the 4th century CE.

The apparent movement of the Sun from one rashi to another is called a {sankranti}. Since there are 12 divisions in a year of 365 days, sankrantis will happen every 30 or 31 days. March 14 is Meena sankranti and April 14 is Mesha sankranti. Mesha sankranti is the beginning of a new year in many Indian calendars.

Box: Vasantotsava and other festivals
The plays {Malavikagnimitram}, attributed to Kalidasa, who is thought to have lived in the 5th century CE, and {Priyadarshika}, attributed to emperor Harshavardhana of Kannauj in the 6th century CE, begin with talk of the same play (that is, {Malavikagnimitram} and {Priyadarshika} themselves) being prepared for the festival of spring, {Vasantotsava}.

Stories of plays by Harshavardhana come from earlier Buddhist sources. The story of Agnimitra is based on a Shunga king from Vidisha (Madhya Pradesh) of the 2nd century BCE. The Shungas came to power after the Mauryas of Pataliputra (Patna). Emperor Ashoka commissioned the great Buddhist {stupa} at Sanchi (Madhya Pradesh). Pushyamitra, the first Shunga, began by destroying the {stupa} and persecuting Buddhists. The next king Agnimitra rebuilt the stupa.

Drinking and throwing coloured water for Vasantotsava appears in {Ratnavali}, a play from the 7th century CE, attributed to Harshavardhana but more likely by a later author. Holi is on Phalguna purnima. It may have emerged as a combination of earlier harvest festivals with the celebration of spring and of forming new relationships. This year the burning of Holika is on Sunday March 28, and the celebration of colours on Monday March 29.