The five limbs
A tithi is the time the Moon takes to gain twelve degrees of separation from the Sun — so the lunar month divides cleanly into thirty of them. Because the Moon moves at an uneven pace, a tithi can run shorter or longer than a calendar day, which is why a date can occasionally repeat or be skipped.
The panchang — literally 'five limbs' — is the traditional Indian almanac, and the tithi is the first and most quoted of its five elements. A tithi is defined astronomically, not by the clock: it is the period during which the angle between the Moon and the Sun increases by exactly twelve degrees. Thirty such steps complete the 360-degree cycle, which is one synodic lunar month.
Because the Moon's apparent speed varies along its orbit, the real-world length of a tithi drifts between roughly nineteen and twenty-six hours. A tithi that ends just after sunrise governs that whole day in most reckonings; one that begins and ends within a single solar day can be 'skipped' (kshaya), and one that spans two sunrises can repeat (vriddhi). This is the source of the occasional 'missing' or 'doubled' date you may notice in a calendar.
The month splits into two halves of fifteen tithis each: the shukla paksha, the bright fortnight waxing toward the full moon, and the krishna paksha, the dark fortnight waning toward the new moon. Knowing which paksha you are in already tells you a great deal about the mood a tradition assigns to the day — bright fortnights generally favour beginnings and growth, dark fortnights favour completion and inward work.
None of this is fortune-telling. The tithi is a precise astronomical coordinate; what each tradition does with it — which days it marks for fasting, festival, or pause — is the interpretive layer built on top. To see the tithi computed for the present moment, open today's live panchang.
There is a way to act on what you have just read — gently, and on your own terms.
