Panchami

Panchami is the fifth tithi of the bright fortnight, and in the fivefold grouping it is a Purna tithi, one of the full or complete days regarded as favourable and stable. Its presiding deities are traditionally the Nagas, the serpent spirits, and the day carries strong serpent associations: Naga Panchami, kept in the bright fortnight of the monsoon month of Shravana, is dedicated to their worship. Vasant Panchami, in the bright fortnight of Magha, honours Saraswati, goddess of learning, and marks the approach of spring. As a Purna tithi with the Moon now near its first quarter, the panchanga reads it as auspicious for a wide range of undertakings. These are the calendar tradition's conventions, resting on the Moon's steady progress toward its waxing quarter.

The Naga association attached to Panchami is old enough to appear across multiple unconnected observances beyond Naga Panchami itself, and some regional calendars keep a separate Naga-related tithi in other months as well, reflecting how central serpent veneration was to agrarian communities for whom snakes were both a genuine hazard and, as predators of rodents, protectors of the grain store. Vasant Panchami's dedication to Saraswati rather than to a serpent deity shows how the same numbered tithi can carry entirely different, non-overlapping associations depending on the month in which it falls, a pattern found throughout the panchanga where a tithi's fivefold classification is stable but its festival content is drawn from a much larger and less systematic body of regional and sectarian tradition.

The tithi is the oldest of the five limbs of the panchanga and the least intuitive, because it is defined by an angle in the sky and not by a sunrise. Panchami occupies the arc from 48 to 60 degrees of that separation. The Moon does not move at a fixed rate, and the same twelve degrees may take a little over nineteen hours near perigee or close to twenty six near apogee. A calendar has to name whole days, so the rule is that whichever tithi is current at sunrise gives the day its name. A tithi shorter than the interval between two sunrises can therefore be skipped entirely, which the tradition calls a kshaya tithi, and one longer than that interval can carry its name over two civil days, an adhika or vriddhi tithi. Both occur in the ordinary course of a year, and both are why an observance can appear on two dates in the same almanac.

Each tithi is halved again, and each half carries a karana, so the first half of Panchami carries Bava, first of the seven movable karanas, and the second Balava, the second movable karana. Seven of the eleven karanas repeat, cycling eight times through the month, while four are fixed to particular half tithis at the month's opening and close.

The Moon is waxing through this arc, setting later each evening and carrying about 21 per cent of the disc lit. That figure is a consequence of the definition rather than an observation added to it: elongation fixes the phase, so naming the tithi already names how much of the disc is lit.