Nakṣatra: The 27-Star Coordinate System
Lunar mansions as celestial coordinates and calendar foundations
Explore the nakṣatra system of 27 lunar mansions, India's indigenous celestial coordinate system, and discover how Indian astronomers detected the precession of equinoxes in the 5th century CE.
Nakṣatra: The 27-Star Coordinate System
Look up at the night sky and you see chaos, thousands of stars scattered without apparent order. But ancient Indians saw something different: a cosmic map, divided into 27 segments called nakṣatras, each marking the Moon's nightly journey through the heavens.
The nakṣatra system is India's indigenous celestial coordinate system, older than the zodiac and intimately tied to the rhythms of the Moon. It remains in use today, determining festival dates, auspicious times, and personal horoscopes for over a billion people.
What Are Nakṣatras?
The Lunar Mansions
The Moon takes approximately 27.3 days to complete one orbit around Earth (relative to the stars). Ancient observers noticed that each night, the Moon appeared near a different star or star group. These 27 stopping points became the nakṣatras, literally "that which does not perish" or "star."
Each nakṣatra spans 13°20' of the celestial sphere (360° ÷ 27 = 13.33°). Together, they divide the entire sky into 27 equal segments, creating a coordinate system that tracks the Moon's position.
The 27 Nakṣatras
The nakṣatras begin with Aśvinī and proceed through the sky:
- Aśvinī (β Arietis) - The Horse-Headed Twins
- Bharaṇī (41 Arietis) - The Bearer
- Kṛttikā (Pleiades) - The Cutters
- Rohiṇī (Aldebaran) - The Red One
- Mṛgaśirā (λ Orionis) - The Deer's Head
- Ārdrā (Betelgeuse) - The Moist One
- Punarvasu (Pollux) - The Return of Light
- Puṣya (δ Cancri) - The Nourisher
- Āśleṣā (ε Hydrae) - The Embracer
- Maghā (Regulus) - The Great One
- Pūrva Phālgunī (δ Leonis) - The Former Red One
- Uttara Phālgunī (β Leonis) - The Latter Red One
- Hasta (δ Corvi) - The Hand
- Citrā (Spica) - The Bright One
- Svātī (Arcturus) - The Independent One
- Viśākhā (α Librae) - The Forked Branch
- Anurādhā (δ Scorpii) - Following Rādhā
- Jyeṣṭhā (Antares) - The Eldest
- Mūla (λ Scorpii) - The Root
- Pūrvāṣāḍhā (δ Sagittarii) - The Former Invincible
- Uttarāṣāḍhā (σ Sagittarii) - The Latter Invincible
- Śravaṇa (Altair) - The Ear
- Dhaniṣṭhā (β Delphini) - The Wealthy
- Śatabhiṣaj (λ Aquarii) - Hundred Physicians
- Pūrva Bhādrapadā (α Pegasi) - The Former Blessed Feet
- Uttara Bhādrapadā (γ Pegasi) - The Latter Blessed Feet
- Revatī (ζ Piscium) - The Wealthy