The five limbs (panchanga)

Five readings from one pair of positions

The Moon moves roughly thirteen degrees a day against the Sun's one, so the angle between them — the elongation — grows steadily through a lunar month and is the raw material for two of the five limbs. The Moon's own position against the fixed backdrop of the 27 nakshatras supplies a third. The remaining two, yoga and vara, mix the Sun back in or step outside the zodiac altogether.

Because tithi, nakshatra and yoga are all divisions of a moving angle, each one is exact at an instant and changes at its own pace: a tithi lasts roughly a day, a nakshatra a little over a day, a karana about half a day. A birth chart or an election candidate reads all five at the exact moment in question; a printed almanac instead reports whichever limb is active at sunrise, with a note for when it ends.

Tithi — the lunar day

A tithi is one twelfth-degree slice of the angle between the Moon and the Sun. The angle runs a full 360 degrees over a lunar month, so dividing it by twelve degrees gives thirty tithis: fifteen while the Moon is separating from the Sun (shukla paksha, waxing) and fifteen while it closes back in (krishna paksha, waning).

Each of the thirty tithis also carries a name based on its position within the fortnight, cycling in a group of five: Nanda, Bhadra, Jaya, Rikta and Purna repeat three times across the fifteen tithis of a paksha. A Rikta tithi (the fourth, ninth or fourteenth of either fortnight) is classically avoided for beginnings, while a Purna tithi is considered complete and steady.

An elongation of 55.78 degrees falls in the fifth twelve-degree slice, so it is the fifth tithi of the waxing fortnight — Shukla Panchami — which by the five-name cycle lands on Purna.

Vara — the weekday

Vara is simply the weekday, but a panchanga's day does not begin at midnight — it begins at local sunrise. A moment before dawn still belongs to the previous day's vara, even though the civil calendar has already turned over. Each weekday is ruled by a graha in the familiar order — Sunday the Sun, Monday the Moon, and so on — and that rulership feeds several other rules, including whether the day's ruler matches the lord of a birth chart's Moon sign.

Where no sunrise can be anchored — a location has not been given, for instance — the vara falls back to the plain civil-date weekday rather than leaving the reading blank.

Yoga — Sun and Moon added together

This yoga is a panchanga limb, unrelated to the yogas of chart combinations described elsewhere. It is built by adding the Sun's and Moon's positions together rather than subtracting one from the other, then dividing that sum by the same thirteen-degree-twenty-minute step used for nakshatras. The result is one of 27 named yogas, from Vishkumbha through to Vaidhriti.

Most of the 27 are neutral or unremarkable, but a handful are classically read as blemishes. Two — Vyatipata and Vaidhriti — are treated as afflicting the entire span the yoga is active for, and are severe enough that the classical literature treats them as ruling out auspicious starts altogether rather than merely counting against them. A second group — Vishkumbha, Atiganda, Shula, Ganda, Vyaghata, Vajra and Parigha — is milder and, in most cases, is read as afflicting only an opening span of the yoga (measured in ghatikas, a classical unit of 24 minutes) rather than the whole thing.

Karana — half a tithi

A karana is half of a tithi: the same lunar-solar angle divided into six-degree steps instead of twelve, giving sixty of them across a lunar month, though several repeat so only eleven distinct names appear. Seven — Bava, Baalava, Kaulava, Taitila, Gara, Vanija and Vishti — are "movable" and cycle repeatedly through the month; four — Shakuni, Chatushpada, Naga and Kimstughna — are fixed and each occurs exactly once, at the start or end of the lunar month.

Vishti, better known by its other name Bhadra, is the karana the classical literature treats most severely: like Vyatipata and Vaidhriti among the yogas, a live Vishti karana is read as ruling out auspicious beginnings for as long as it lasts, not merely as a point deduction. Shakuni, Chatushpada and Naga are also classically listed among the karanas to avoid, though read as milder than Vishti.

At an elongation of 87.54 degrees, dividing by six degrees places the moment in the fifteenth karana slot of the month, which by the seven-name movable cycle is Vishti — independently, the classical rule that Bhadra occupies the first half of the eighth tithi of the waxing fortnight agrees, since that is the tithi the same moment falls in.