What is a panchang?

The five limbs

Vara is the weekday, ruled by one of the seven classical planets. Tithi is the lunar day: one thirtieth of a lunation, measured as the Moon gaining 12° of elongation on the Sun. Nakshatra is the segment of 13°20′ the Moon currently occupies, one of 27. Yoga is a division of the combined longitude of Sun and Moon, also 27 of them, and has nothing to do with the yoga of practice. Karana is half a tithi.

Four of the five are Moon-driven, which is why a panchang changes so quickly. The Moon moves about 13° a day, so it crosses a nakshatra boundary roughly once every twenty-four hours — and almost never at midnight.

Why the timings are not round numbers

A tithi is not a day. Because the Moon's speed varies through its orbit, a tithi runs anywhere from about 20 to about 27 hours. The same is true of every other limb. A panchang that gives whole-day values is rounding away the thing that makes it useful, which is the exact moment a limb changes.

This also means a limb can be skipped or repeated across a calendar day, which is normal and not an error.

Why your city matters

The limbs are conventionally quoted as they stand at sunrise, and sunrise depends on where you are. Kolkata sees sunrise around fifty minutes before Rajkot. That shifts the whole day: rahu kaal, every choghadiya boundary and every hora move with it.

A single national panchang is therefore wrong for almost everyone reading it. The difference is not academic — it is routinely half an hour or more on the windows people actually plan around.

Ayanamsa, and why we state it

Nakshatras are defined on the sidereal zodiac, measured from a fixed stellar reference rather than from the equinox. The offset between the two frames is the ayanamsa, currently about 24°. Different schools use slightly different values.

Near a boundary that difference moves the Moon into a neighbouring nakshatra or pada and changes the entire reading. That is why every page here states which ayanamsa produced its figures — Lahiri, the Indian government standard, unless you change it. A panchang that does not tell you cannot be reproduced.

Questions