Nakshatraनक्षत्र

A nakshatra, or lunar mansion, is one of 27 equal segments of the zodiac, each spanning 13°20' (360° divided by 27). The set is the oldest layer of Indian astronomy — the Moon, moving about 13.2° per day, transits roughly one nakshatra each day, which is what makes them a natural lunar calendar. Each carries a name, a ruling planet, and a presiding deity.

The nakshatra is computed from the sidereal longitude of the Moon — the tropical position from the Swiss Ephemeris with the Lahiri ayanamsa subtracted — divided into 13°20' bands. For the panchanga, the nakshatra reported for a date is the one occupied by the Moon at sunrise, and its end time is the moment the Moon’s longitude next crosses a band boundary, found by bisection and shown in the location’s timezone.

The nakshatra also reaches beyond the daily almanac. In a natal chart, the Moon’s nakshatra at birth — and the quarter (pada) within it — anchors the Vimshottari dasha sequence, the timeline of planetary periods. That dependence is one reason SahiKundli uses sidereal positions throughout: a tropical reckoning would place the Moon in the wrong nakshatra by roughly one full mansion.

Brihat Samhita Chapter 98 is one classical source for the functions and traditional qualities assigned to nakshatras. It helps explain the inherited activity language; it does not change the computed lunar longitude. Read the Brihat Samhita source note.