The Navagrahas (Sanskrit nava, "nine", and graha, "seizer") are the nine celestial influences used in Jyotisha, the astronomical and astrological limb of the Vedas. Five are the naked-eye planets known since antiquity, Mars, Mercury, Jupiter, Venus and Saturn; two are the luminaries, the Sun and Moon; and two, Rahu and Ketu, are the north and south lunar nodes, the invisible points that govern eclipses. Together they form the basis of every horoscope, of the planetary periods (dashas), and of the weekday names: Sunday to Saturday follow the Sun, Moon, Mars, Mercury, Jupiter, Venus and Saturn in that order.
How the grahas are classified
Classical texts such as Brihat Parashara Hora Shastra divide the grahas into natural benefics (Jupiter, Venus, a well-associated Mercury and a waxing Moon) and natural malefics (the Sun, Mars, Saturn, Rahu and Ketu). Each graha has signs of exaltation (uchcha) and debilitation (neecha), one or two own signs, a moolatrikona sign of special strength, and natural relationships of friendship, enmity or neutrality with the others. The seven visible grahas each rule one or two of the twelve rashis, and every graha rules three of the 27 nakshatras, which determines the Vimshottari dasha sequence of 120 years.
Worship and temples
Navagraha shrines, with the nine deities arranged in a square facing different directions, are found in most South Indian Shiva temples. In Tamil Nadu, nine temples around Kumbakonam are each dedicated to one graha and form a popular pilgrimage circuit. Each graha has a beeja (seed) mantra, a gemstone, a grain, a colour and a weekday traditionally associated with it. Navagraha homa and shanti rituals are performed to seek the favour of all nine.
Astrological significations, remedies and gemstone associations described on these pages are traditional beliefs presented for cultural and educational purposes. The astronomical facts are given separately for each graha.