The 27 Nakshatras: The Moon's Star Map, Explained with the Astronomy

The nakshatras are 27 equal divisions of the ecliptic - the path the sun, moon and planets trace through the sky - each spanning exactly 13 degrees 20 minutes of arc and named for the stars that mark it. Twenty-seven arcs of 13°20' tile the full 360-degree circle precisely, and the day's nakshatra in the panchang is simply the arc the moon occupies at that moment. It is one of the oldest pieces of systematic astronomy in continuous use anywhere: the nakshatras are named in Vedic texts composed millennia ago. Those early lists began with Krittika rather than Ashwini, and the Atharvaveda counts 28, with Abhijit; the 27 equal arcs a modern ephemeris computes are the later, standardised form.

Why 27? The moon's own rhythm

The number is not decorative. The moon takes about 27.3 days to complete one circuit of the sky relative to the stars - its sidereal period. Divide the sky into 27 stations and the moon spends close to one day in each: it enters a nakshatra, crosses its 13°20' over roughly 24 hours, and moves on. The ancients effectively turned the moon into the hand of a clock and the nakshatras into its dial. The fit is close but not exact - the moon's elliptical orbit makes it linger up to a few hours longer in some nakshatras and hurry through others - which is why the panchang lists an end-time for the day's nakshatra rather than assuming a neat midnight-to-midnight day.

Some traditions also count a 28th, Abhijit, a short intercalary segment carved from the end of Uttara Ashadha and the start of Shravana. It is not one of the 27 equal divisions, but muhurat practice remembers it fondly - the midday Abhijit muhurat takes its name from it.

The 27 nakshatras

1 to 9	10 to 18	19 to 27
Ashwini	Magha	Mula
Bharani	Purva Phalguni	Purva Ashadha
Krittika	Uttara Phalguni	Uttara Ashadha
Rohini	Hasta	Shravana
Mrigashira	Chitra	Dhanishta
Ardra	Swati	Shatabhisha
Punarvasu	Vishakha	Purva Bhadrapada
Pushya	Anuradha	Uttara Bhadrapada
Ashlesha	Jyeshtha	Revati

Many of the anchor stars are ones you can find tonight. Krittika is the Pleiades cluster; Rohini is the bright orange star Aldebaran; Chitra is Spica; Jyeshtha is the red heart of Scorpius, Antares. When the panchang says the moon is in Rohini, the moon really is passing near Aldebaran - step outside and check. Tamil and Malayalam calendars use their own names for many of the 27: Shravana is Thiruvonam in both, and Jyeshtha is Kettai in Tamil and Thrikketta in Malayalam. The sequence also maps neatly onto the rashis: each 30-degree rashi contains exactly two and a quarter nakshatras, which is why Jyotish divides every nakshatra into four padas (quarters) - nine padas to a rashi, the bridge between the moon's 27-fold map and the sun's 12-fold one.

Janma nakshatra: your birth star

Your janma nakshatra is the nakshatra the moon occupied at the moment you were born - a precise astronomical coordinate, recoverable from your birth date, time and place. The tradition builds a great deal on it: the first syllable of a name is often chosen from the janma nakshatra's prescribed sounds, the nakshatra sets your place in matching calculations before a marriage, and it anchors the dasha periods used in Jyotish. A kundali computes it as its very first step, because every other lunar factor in the chart hangs off where the moon was. If you know your birth time even roughly, your janma nakshatra is usually unambiguous; only births within a few hours of a nakshatra boundary need the time pinned down carefully.

Why nakshatra matters in muhurat selection

Of the five limbs of the panchang, nakshatra carries perhaps the most weight in fixing a muhurat. The tradition classifies the 27 into groups by temperament - some counted gentle and favourable for beginnings, like Rohini, Pushya, Hasta and Anuradha; others counted sharp or fierce and reserved for different kinds of work. A purohit fixing a date for a wedding, a griha pravesh or an upanayanam will typically look for the day's nakshatra to be one of the prescribed set for that ritual, then cross-check tithi, vara and yoga around it. Marriage muhurats are the fullest example of this filtering - our post on how marriage dates are fixed walks through the whole sieve, and nakshatra is one of its finest meshes.

The astronomy underneath is straightforward: because the moon changes nakshatra about once a day, the nakshatra filter alone admits or rejects whole days at a time, which is why "good dates" cluster and why two auspicious windows can sit weeks apart.

An old science, still running

What is quietly remarkable about the nakshatra system is how cleanly it separates observation from interpretation. The divisions are pure geometry - 27 equal arcs, fixed against the stars. The meanings layered on them are tradition, held and transmitted with care. You can honour both at once: the panchang on Purohit.app computes the moon's position from planetary data using the Swiss Ephemeris and reports the nakshatra and its end-time to the minute, and what that nakshatra means for your naming ceremony or wedding date remains exactly what the tradition has always held it to mean.