The panchanga is named for its five limbs, and the name is the argument: it is one instrument with five readings, not five lists that happen to share a page. An almanac gives all five for every day, and a practitioner choosing a moment consults them together.
Three of the five are angular relationships between the Sun and the Moon, and they differ only in how finely the same angle is cut.
- The tithi is the elongation of the Moon from the Sun in steps of twelve degrees. Thirty of them span a lunar month.
- The karana is half a tithi, so sixty fill the month, and it cuts the same measure at six degrees.
- The nitya yoga is not a difference but a sum: the longitudes of Sun and Moon added together, divided into twenty-seven parts of thirteen degrees twenty minutes.
The remaining two are independent of that pair. The vara is the weekday, the only limb that runs on a seven-day cycle owing nothing to the Moon. The nakshatra is the Moon's own position against the fixed stars, in twenty-seven divisions of the same thirteen degrees twenty minutes that the nitya yoga uses.
Because the tithi and the karana are defined by an angle rather than by a day, they do not keep step with sunrise. A tithi can begin and end within one day, so that no sunrise falls inside it and it is expunged from the calendar; it can also span two sunrises and be repeated. This is why a festival fixed to a tithi can appear to skip a date or fall on two, and why almanac makers who use different rules for assigning a tithi to a civil day publish different festival dates in the same year.
The five limbs are read as a set. A tithi favourable in itself can be overridden by an inauspicious yoga or by the karana Vishti, and the classical muhurta texts are largely concerned with how the limbs qualify one another.
Read alone, each limb is a list of names with verdicts attached. Read together, they are a technology for selecting a moment, which is what they were built to be.