Nakshatra: the 27 lunar mansions

Equal parts of the sidereal zodiac

• 27 nakshatras of 13°20′ each, starting with Ashwini at 0° of sidereal Mesha (Aries).
• Each has four padas (quarters) of 3°20′, so the 108 padas fit the twelve signs exactly: two and a quarter nakshatras per sign.
• Each has a lord. Nine lords — Ketu, Venus, Sun, Moon, Mars, Rahu, Jupiter, Saturn, Mercury — repeat three times around the circle. That sequence is the order of the Vimshottari dasha.

The Moon moves about 13° a day, so it spends roughly a day in each nakshatra — longer when it moves slowly near apogee, shorter near perigee. Some muhurta traditions add a 28th, Abhijit, between Uttara Ashadha and Shravana; the website uses the standard 27.

Worked example

Why the ayanamsha moves nakshatra times

Unlike the tithi, the nakshatra is measured in the sidereal zodiac, so it depends on the ayanamsha — the offset between the equinox and the stars. At the Moon’s speed in the example, one arcminute of ayanamsha moves a nakshatra boundary by about 2.0 minutes, and one degree by about 2.0 hours.

Ayanamshas in use differ from Lahiri by a few arcminutes (Krishnamurti) to about a degree and a half (Raman), so the same moment can fall in different nakshatras in different schools. The website uses Lahiri as a linear model within about an arcminute of published tables; against Drik Panchang its nakshatra endings agreed within 0.7 minutes on 28 cases.

All 27 nakshatras