The five limbs
Panchang means five limbs: tithi, vara, nakshatra, yoga and karana. Together they describe the quality of a moment in the traditional Indian calendar, and the set computed for the moment of a birth is read as a description of the day a person entered.
Tithi and karana
The tithi is the lunar day, measured by the angular distance between the Sun and the Moon, and each of the thirty tithis carries its own character. The karana is half a tithi. Both are used in naming, in fixing observances, and in judging which activities suit a day.
Yoga and vara
The yoga here is not a chart combination but one of twenty-seven divisions derived from the combined longitudes of the Sun and Moon. The vara is simply the weekday, ruled by its planet, and it is the limb that determines rahu kaal and the choghadiya sequence.
Common questions
What is a tithi?
The lunar day, measured by the angle between the Sun and the Moon. There are thirty in a lunar month, and each carries its own character.
Why does my tithi not match the calendar date?
A tithi is not tied to midnight. It begins and ends whenever the Sun–Moon angle reaches the right value, so it can start and finish part-way through a civil day.