Ketu, the south lunar node, is a shadow planet (chhaya graha) in Vedic astrology, representing the tail of the demon Rahu. Unlike physical planets, Ketu is a mathematical point where the Moon's orbit crosses the ecliptic. Its origin is described in the Puranas: during the churning of the ocean (Samudra Manthan), the demon Svarbhanu (Rahu) drank nectar and was beheaded by Vishnu; the head became Rahu and the torso Ketu (Matsya Purana 247.16-17). Ketu is associated with spirituality, detachment, moksha, and hidden influences.
In mantra-shastra, the beej mantra for Ketu is 'Stram' (स्राम्), composed of 'Sa' (sattva), 'Ra' (fire), 'A' (Vishnu), and 'M' (bindu representing the void). The full mula mantra 'Om Straam Streem Straum Sah Ketave Namah' is prescribed in the Mantra Mahodadhi (Chapter 14) for propitiating Ketu. Chanting this mantra 108 times daily, especially on Tuesdays or during Ketu hora, is believed to remove obstacles, alleviate afflictions like sudden losses, skin diseases, and confusion, and enhance spiritual insight. The Devi Mahatmya (Chapter 11) also references Ketu as a deity who protects the devotee during the recitation of the Devi Kavacham.
Traditional texts like the Brihat Parashara Hora Shastra (Chapter 3) detail Ketu's effects: it grants liberation (moksha) when strong, but causes detachment and instability when afflicted. The recommended chanting count is 18,000 times (one purashcharana) for significant results. Ritual setting includes a smoky or brown altar, offering sesame seeds, black cloth, and mustard oil lamp. Cautions: Ketu is a shadow planet; excessive chanting without guidance may lead to excessive detachment or confusion.
It is best chanted with a clear intention and under the supervision of a guru. The mantra should not be chanted during eclipses or on Amavasya without proper purification.
Om, to Ketu, the one with the banner, salutations.
The mantra contains the three seed syllables srāṁ, srīṁ, srauṁ, which are variations of the primary Ketu beej 'srāṁ' (स्राम्). 'Srāṁ' combines 'Sa' (sattva), 'Ra' (fire), 'A' (Vishnu), and 'M' (bindu representing the void). The three forms represent creation, preservation, and dissolution.