What is a nakshatra? The 27 lunar mansions and how to find yours

Ask a Hindu family what their nakshatra is and most will know it the way they know their blood group. Ask what a nakshatra actually is, and the answers get vaguer.

It is simpler than it sounds. A nakshatra is one of twenty-seven equal slices of the sky along the Moon's path.

How it is measured

The belt of sky the Sun, Moon and planets travel through is 360 degrees around. Divide it into twenty-seven and each slice is thirteen degrees and twenty minutes. The Moon takes about 27.3 days to go all the way round, so it spends roughly a day in each — which is why a nakshatra is closer to a lunar day than to anything about stars you could point at.

Each nakshatra is split again into four quarters called padas, each of three degrees twenty minutes. Twenty-seven times four is 108, and 108 padas is exactly nine to each of the twelve signs — a number you will meet again in the tradition.

The sidereal sky

The measurement is made against the fixed stars, the sidereal zodiac, not against the seasons as Western astrology does. The two differ by about twenty-four degrees today. It is why a person's Vedic Moon sign is so often different from the sign they were taught as theirs, and why asking for your nakshatra by looking up a Western chart gives the wrong answer.

What it is used for

Your janma nakshatra — the one the Moon occupied at your birth — does a lot of quiet work:

• It sets the dasha you were born into. Each nakshatra has a ruling graha, and the order repeats three times through the twenty-seven, so your nakshatra decides which period of life your chart starts in.
• Its first syllable is traditionally used to choose a name.
• It is half of what kundali matching is calculated from.
• It is one of the five limbs of the daily panchang, where the nakshatra the Moon is in today is listed.

The twenty-seven, in order

Ashwini, Bharani, Krittika, Rohini, Mrigashira, Ardra, Punarvasu, Pushya, Ashlesha, Magha, Purva Phalguni, Uttara Phalguni, Hasta, Chitra, Swati, Vishakha, Anuradha, Jyeshtha, Mula, Purva Ashadha, Uttara Ashadha, Shravana, Dhanishta, Shatabhisha, Purva Bhadrapada, Uttara Bhadrapada and Revati.

The ruling grahas run in a fixed cycle through them — Ketu, Venus, Sun, Moon, Mars, Rahu, Jupiter, Saturn, Mercury — and then start again. So Ashwini, Magha and Mula share Ketu; Bharani, Purva Phalguni and Purva Ashadha share Venus; and so on.

Why you need your birth time

You cannot find yours from a date alone. The Moon crosses a nakshatra boundary roughly once a day, so on any given date it may have been in one nakshatra in the morning and the next by evening. A birth at 6 a.m. and one at 9 p.m. on the same day can belong to different ones.

You need the date, the time and the place — the place because it fixes the exact moment against the sky.

Our free kundali works out your nakshatra, its pada and the dasha you were born into from a real ephemeris, and shows them beside your chart. It is the one detail from a birth time that most people already know the name of and have never been able to check.