Ketu is the descending lunar node. Ketu is what remains of the body of Rahu. It is a malefic planet, and is always 180 degrees apart from that of Rahu. Ketu is a headless half-planet, shadowy as Rahu and malefic, though not as malefic as Rahu. Ketu's effects are similar to those of Mars, but this is only one way of describing the malefic effect and power of Ketu. etu also does not rule any zodiac sign since it is not a real planet.

Ketu is known as "Moksha- Karaka" or the planet influencing spirituality. According to Hindu mythology, Ketu is the rest of the body of Rahu, while Rahu is the head. Ketu goes along beautifully with Mercury, Venus, Saturn and Rahu.