Actually an imaginary planet, Rahu is instrumental in strengthening the power and can convert enemies into friends. It is popularly called the Planet of Success. It is a node positioned at the meeting point of earth's trajectory around the Sun and the Moon's trajectory around the Earth.
Rahu is believed to represent the head of the demon. When Rahu, Sun and Moon are in the same zodiacal longitude, solar eclipse takes place. Being a shudra graha, it rules over thieves, witches, magicians, venom and poison, snakes and thorny bushes, jails and isolated places, un habituated places, hypnotists etc. As Rahu is not a real planet, it does not rule any zodiac sign.
