What is a nakshatra?
A nakshatra is a lunar mansion, one of 27 equal segments covering the entire sidereal zodiac. Each segment spans 13°20′ (360° ÷ 27). The nakshatra the Moon occupies changes roughly once a day, and it is the Moon's position at sunrise that names the day's nakshatra in panchangam.
While tithi (the lunar day) measures the distance between Moon and Sun, nakshatra measures the Moon's absolute position in the sky. Tithi tells you how far the Moon is from the Sun. Nakshatra tells you which stars the Moon currently stands in front of.
All 27 nakshatras with padas and rashis
Each nakshatra is divided into four quarters called padas, each spanning 3°20′. The padas connect the nakshatra and rashi systems: 27 nakshatras × 4 padas = 108 quarters, distributed across 12 rashis with 9 quarters (= 2.25 nakshatras) per rashi.
| No. | Tamil | Transliteration | Degrees | Rashi (padas) |
|---|---|---|---|---|
| 1 | அசுவினி | Ashwini | 0°–13°20′ | Mesha (all 4) |
| 2 | பரணி | Bharani | 13°20′–26°40′ | Mesha (all 4) |
| 3 | கார்த்திகை | Krittikai | 26°40′–40° | Mesha (1) / Rishabha (2–4) |
| 4 | ரோகிணி | Rohini | 40°–53°20′ | Rishabha (all 4) |
| 5 | மிருகசீரிடம் | Mrigashirsham | 53°20′–66°40′ | Rishabha (1–2) / Mithuna (3–4) |
| 6 | திருவாதிரை | Thiruvadhirai | 66°40′–80° | Mithuna (all 4) |
| 7 | புனர்பூசம் | Punarpoosam | 80°–93°20′ | Mithuna (1–3) / Kataka (4) |
| 8 | பூசம் | Poosam | 93°20′–106°40′ | Kataka (all 4) |
| 9 | ஆயில்யம் | Ayilyam | 106°40′–120° | Kataka (all 4) |
| 10 | மகம் | Magam | 120°–133°20′ | Simma (all 4) |
| 11 | பூரம் | Pooram | 133°20′–146°40′ | Simma (all 4) |
| 12 | உத்திரம் | Uthiram | 146°40′–160° | Simma (1–2) / Kanni (3–4) |
| 13 | அஸ்தம் | Astham | 160°–173°20′ | Kanni (all 4) |
| 14 | சித்திரை | Chithirai | 173°20′–186°40′ | Kanni (1–2) / Thula (3–4) |
| 15 | சுவாதி | Swathi | 186°40′–200° | Thula (all 4) |
| 16 | விசாகம் | Visakam | 200°–213°20′ | Thula (1–3) / Vrischika (4) |
| 17 | அனுஷம் | Anusham | 213°20′–226°40′ | Vrischika (all 4) |
| 18 | கேட்டை | Kettai | 226°40′–240° | Vrischika (all 4) |
| 19 | மூலம் | Moolam | 240°–253°20′ | Dhanus (all 4) |
| 20 | பூராடம் | Pooradam | 253°20′–266°40′ | Dhanus (all 4) |
| 21 | உத்திராடம் | Uthiradam | 266°40′–280° | Dhanus (1–2) / Makara (3–4) |
| 22 | திருவோணம் | Thiruvonam | 280°–293°20′ | Makara (all 4) |
| 23 | அவிட்டம் | Avittam | 293°20′–306°40′ | Makara (1–2) / Kumbha (3–4) |
| 24 | சதயம் | Sadhayam | 306°40′–320° | Kumbha (all 4) |
| 25 | பூரட்டாதி | Poorattadhi | 320°–333°20′ | Kumbha (1–3) / Meena (4) |
| 26 | உத்திரட்டாதி | Uthirattadhi | 333°20′–346°40′ | Meena (all 4) |
| 27 | ரேவதி | Revathi | 346°40′–360° | Meena (all 4) |
Your birth nakshatra, your astrological identity
The single most important piece of information in Tamil astrology is your birth nakshatra (janma nakshatra), the nakshatra the Moon was in when you were born. It is used for:
- Rashi (zodiac sign), your birth nakshatra determines your Tamil zodiac sign. Each sign contains 2–3 nakshatras, and the pada specifies which sign you belong to.
- Tarabalam, daily star-strength calculated from the distance (in nakshatras) between your birth nakshatra and the day's nakshatra. 9 tara groups alternating favourable and unfavourable.
- Chandrashtamam, the Moon's transit through your 8th sign, a personal unfavourable period recurring roughly every 27 days.
- Porutham, the 10 Tamil marriage compatibility checks that compare the bride's and groom's birth nakshatras and padas.
- Naming, the Tamil naming system assigns a syllable based on the pada of your birth nakshatra.
How nakshatra is calculated
Nakshatra requires the Moon's sidereal position, its position corrected for the slowly drifting gap between the tropical and sidereal zodiacs. This correction is called ayanamsa.
Worked example
Worked example
- Moon's tropical longitude (Meeus ch. 47)
- 42.15°
- Lahiri ayanamsa (2026)
- 24.22°
- Moon's sidereal longitude
- 42.15° − 24.22° = 17.93°
- Nakshatra width
- 360° ÷ 27 = 13.333°
- Nakshatra index
- ⌊17.93 / 13.333⌋ = 1 → Bharani (no. 2, index 1)
- Pada
- ⌊(17.93 − 13.333) / 3.333⌋ + 1 = 2 → Bharani pada 2
Nakshatra: Bharani, pada 2, in rashi Mesha (Aries).
Our calculator uses Meeus's 60-term series for the Moon's position and Lahiri (Chitrapaksha) ayanamsa with 23.85° at J2000.
Note the difference from tithi: tithi uses the Moon−Sun difference and is therefore ayanamsa-independent. Nakshatra uses the Moon's absolute sidereal position, so it depends on which ayanamsa model you choose. We use Lahiri (Chitrapaksha), the standard for Tamil panchangams and the Indian government's official calendar.
Nakshatras and festivals
Several major festivals are tied to specific nakshatras rather than tithis:
- Thiruvonam (22nd nakshatra), Onam, Kerala's harvest festival, celebrated when the Moon is in Thiruvonam in the month of Avani.
- Thiruvadhirai (6th nakshatra), Arudra Darshan, Shiva's cosmic dance, celebrated in the month of Margazhi.
- Visakam (16th nakshatra), Vesak/Vaishakhi, the Buddhist birth festival, and the Visakam temple festival.
- Poosam (8th nakshatra), Thai Poosam, Murugan's festival with kavadi pilgrimage.
- Magam (10th nakshatra), Maha Magam, the great bathing festival every 12 years at Kumbakonam.
- Swathi (15th nakshatra), considered auspicious for new beginnings and the pursuit of knowledge.
Nakshatra and location
Like tithi, the astronomical nakshatra is the same everywhere at any given instant, the Moon occupies the same part of the sky for the entire Earth. But because sunrise varies, the nakshatra prevailing at sunrise can differ. A city with early sunrise may still have yesterday's nakshatra.
Our calculator handles this correctly by computing nakshatra at the local sunrise in the selected city. This is why you may see a different day-nakshatra in Copenhagen than in Chennai, not because the Moon is elsewhere, but because sunrise falls in a different part of the nakshatra cycle.
Nakshatra vs. Western astrology
Western astrology uses the tropical zodiac, defined by the spring equinox, which slowly drifts relative to the stars. Tamil astrology uses the sidereal zodiac, anchored to the actual star positions via Lahiri ayanamsa. The difference is currently about 24° and growing at roughly 50 arcseconds per year.
This means a nakshatra corresponds to an actual group of stars in the sky. The Ashwini segment points toward the stars in the Ram's head; Rohini toward the orange beacon of Aldebaran in Taurus. The tropical zodiac has drifted so far from the stars that the Western "Aries" now lies in the star group Pisces.