Rahu

Rahu is one of the nine grahas of Hindu astrology, and with his counterpart Ketu he forms a pair that the Sanskrit sources call the shadow grahas, for they are not visible bodies with discs of their own but points of darkness, in astronomical terms, the two nodes where the moon's path crosses the ecliptic, the places where eclipses occur. Their nature is explained by a myth attached to the churning of the ocean. When the gods had won the nectar of immortality, the amrita, and were sharing it out, the demon Svarbhanu slipped into the line of the gods in disguise to steal a taste; but the Sun and the Moon recognised him and reported him, and Vishnu struck off his head with his discus at the very moment the nectar reached his throat, so that the head, already made immortal, could not die.

The severed immortal head is Rahu and the body is Ketu, and Rahu, in eternal enmity toward the Sun and Moon who exposed him, pursues them across the sky and from time to time seizes and swallows them; but because he has no body below the throat, they pass out again through his open neck, and the sun or moon reappears. This is the traditional Hindu explanation of eclipses. In astrology Rahu is a powerful and unsettling influence, associated with sudden events, foreign things, worldly desire and disruption, feared and carefully propitiated. He is the deathless head of a demon, forever hungry and forever unsatisfied.

Rahu, like his counterpart Ketu, has a fixed devotional address within the Navagraha temple circuit of the Kaveri delta in Tamil Nadu: the shrine at Thirunageswaram, near Kumbakonam, built specifically to address the astrological influence of the ascending node. The temple's presiding image shows Rahu with a human torso and face merging into a serpent's coiled lower body, a form distinct from South Indian depictions of him as a disembodied head alone, and the site's iconographic program associates the shadow planet closely with naga, snake, imagery generally, reflecting an old and widespread Indian association between eclipses, serpents and the swallowing of light.

Devotees visiting as part of the full nine temple circuit typically address Rahu's shrine seeking relief from sudden setbacks, unexplained anxiety, professional obstruction or difficulties attributed to an afflicted node in the birth chart, treating him as the planet most associated with disruption arriving without visible warning. The temple's continued function as an active pilgrimage site, drawing worshippers from across South India specifically for astrological remedy rather than general devotion, shows how a myth explaining the mechanics of eclipses was translated, over centuries, into a standing institution of ritual practice addressed to a body that, astronomically speaking, occupies no fixed place in the sky at all.