Ketuकेतु

Ketu is the ninth and last of the Navagraha, and like Rahu he is not a planet but a point: the descending lunar node, where the moon's orbit crosses the ecliptic going south.

Mythologically he is the body without a head — the remainder of the asura Svarbhanu after Vishnu's discus severed him at the moment the stolen nectar passed his throat. Rahu is the head; Ketu is what was left below it. Both are immortal, and both were made grahas.

Where Rahu is associated with grasping, Ketu is associated with release. In the astrological tradition he governs detachment, loss, renunciation, unexplained events, and — significantly — moksha, liberation. He is the graha that removes rather than adds, and the texts treat that removal as ambiguous: painful in worldly terms, useful in spiritual ones.

His name means banner or flag, and in older Sanskrit it also denotes a comet or any bright appearance in the sky.

He is the most abstract figure in the Hindu pantheon: a headless body identified with a mathematical point, worshipped for the capacity to take things away.

Ketu's origin is the same episode as Rahu's — the churning of the ocean, the theft of the nectar, the exposure by Surya and Chandra, and the beheading. The Bhagavata and Vishnu Puranas give the fullest accounts.

What distinguishes his development is the astronomical mapping. Indian astronomy required two nodes to account for eclipses: one where the moon crosses the ecliptic northward and one southward. The single severed asura supplied exactly two immortal pieces, and the correspondence was made — Rahu the ascending node, Ketu the descending.

His name has an older and looser use. In the Rigveda ketu means a banner, a mark, a bright appearance, and the word is applied to comets and unusual celestial phenomena. That earlier sense survives in his association with things that appear without explanation.

In some accounts Ketu's body is joined to the head of a serpent, completing the pairing in which the two nodes are the head and tail of a great snake encircling the ecliptic — the Naga association that runs through South Indian node worship.

As a graha he enters the Navagraha scheme in the early centuries CE. The Brihat Parashara Hora Shastra gives him detachment, spiritual insight, sudden loss, and matters that resist ordinary explanation.

Ketu is shown as a headless torso, and where the figure is completed it is with a serpent's head rather than a human one.

He is smoky or variegated in complexion, and rides a vulture or a chariot drawn by eight horses of mixed colour — the variegation being part of his character.

He carries a mace or club, and often a flag or banner, following his name.

As a Navagraha he faces north in the nine-planet shrine, opposite Rahu's southern position — the two set against each other as the nodes are.

His gem is cat's eye (lehsunia), his grain horse gram (kulthi), his cloth grey or multi-coloured, and his direction northwest.

In South Indian temples he is often installed as a serpent alongside Rahu, and the two are worshipped together as a pair rather than singly.

Ketu as a Navagraha — the ninth of the nine, his principal presence.

The descending node — his astronomical identity.

Dhvajaketu — the banner form, following the older meaning of his name.

Naga Ketu — the serpent form, worshipped in the south alongside Naga Rahu.

Ketu as comet — the older Vedic usage, in which ketu names any unexplained bright appearance; not a worshipped form but the semantic root of his character.

The severance. At the distribution of the amrita by Mohini, the asura Svarbhanu disguises himself among the gods and drinks. Surya and Chandra expose him; Vishnu's discus takes off his head. The nectar has reached his throat, so both parts live. The head becomes Rahu, the body Ketu.

The serpent joining. In several accounts the headless body is joined with a serpent's head, or the serpent Ketu is a distinct being merged with the torso — which is the narrative basis for the naga associations.

The eclipse. Rahu swallows the sun or moon and they pass through him; the story is told of Rahu, but eclipses occur at either node, and Ketu's is the second of the two.

Ketu and liberation. The astrological tradition, rather than the narrative one, supplies his most distinctive material: he is the graha of moksha, and a strong Ketu is read as indicating detachment and spiritual inclination. There is no Puranic story that establishes this; it is a technical doctrine that grew from his headlessness — a body without the organ of thought and appetite.

Ketu is worshipped almost entirely alongside Rahu, and the two are rarely approached separately.

The Rahu-Ketu Sarpa Dosha rite at Srikalahasti in Andhra Pradesh is the principal observance, performed continuously through the day and drawing very large numbers.

His offerings are grey or multi-coloured cloth, horse gram (kulthi), sesame, and cat's eye where a gem is used. Tuesday, and in some regions Saturday, is his day.

In the Navagraha shrine he is circumambulated in the prescribed order and faces north.

Naga worship overlaps substantially with his: milk offered to serpent images, and observances at naga shrines, are frequently understood in connection with the nodes in South Indian practice.

In the astrological tradition his seven-year period (mahadasha) and his placement are read in connection with detachment, unexplained difficulty and spiritual inclination. As with Rahu and Shani, these are beliefs held within Jyotisha and are described here rather than endorsed; the same caution about commercially sold ritual applies.

The Navagraha Stotra, the Ketu Kavacham and ॐ कें केतवे नमः are the standard recitations.

Keezhperumpallam (Vanagiri), Tamil Nadu — his shrine among the nine Navagraha temples around Kumbakonam, and the principal Ketu temple in India.

Srikalahasti, Andhra Pradesh — the main site for Rahu-Ketu rites, performed for both nodes together.

Ketu shrines within Navagraha groups across South Indian temples, installed facing north.

Naga temples where the nodes are worshipped in serpent form, including Kukke Subramanya and Mannarasala in Kerala.

He has no independent temples in North India; node worship there is minimal.

Ketu is the only deity in the Hindu tradition whose entire character derives from an absence. He is a body without a head — without the seat of thought, appetite, speech and identity — and the astrological tradition built his meaning directly on that: he governs what is given up, what falls away, and what cannot be explained.

The pairing with Rahu is the tradition's neatest piece of symmetry. One asura, one blow, two immortal halves, and they are assigned opposite functions: the head that endlessly grasps and cannot hold, and the body that cannot grasp at all. Ambition and renunciation, produced by the same cut, positioned at opposite points of the same orbit. Whatever one makes of the astrology, the construction is unusually well made.

His association with moksha is the most surprising assignment in the Navagraha scheme. The graha of loss is also the graha of liberation, and the tradition does not treat these as different things — what liberation removes is precisely what a person would rather keep. That the most inauspicious-seeming of the nine is the one associated with the tradition's highest goal is a genuine piece of theological nerve.

And like Rahu, he is a point in space with a shrine. The nine grahas of Hindu worship include seven visible bodies and two intersections of orbits, and the tradition gave all nine faces, weapons, mounts, gems and grains. It is a strange and rather magnificent thing to have done.