Rahu

Rāhu (Sanskrit: राहु, ) is one of the nine major celestial bodies (navagraha) in Hindu texts and the king of meteors. It represents the ascension of the Moon in its precessional orbit around the Earth, also referred to as the north lunar node, and along with Ketu, is a "shadow planet" that causes eclipses. Despite having no physical existence, Rahu has been allocated the status of the planet by ancient seers owing to its strong influence in astrology. Rahu is usually paired with Ketu, the south lunar node. The time of day considered to be under the influence of Rahu is called Rāhu kāla and is considered inauspicious. As per Hindu astrology, Rahu and Ketu have an orbital cycle of 18 years and are always 180 degrees from each other orbitally (as well as in the birth charts). This coincides with the precessional orbit of the Moon or the ~18 year rotational cycle of the lunar ascending and descending nodes on the Earth's ecliptic plane. This also corresponds to a saros, a period of approximately 223 synodic months (approximately 6585.3211 days, or 18 years, 11 days, 8 hours), that can be used to predict eclipses of the Sun and Moon. Rahu rules the zodiac sign of Aquarius together with Shani (traditional ruling planet). Astronomically, Rahu and Ketu denote the points of intersection of the paths of the Sun and the Moon as they move on the celestial sphere. Therefore, Rahu and Ketu are respectively the personification in Hindu astrology of north and the south lunar nodes. Eclipses occur when the Sun and the Moon are at one of these points, giving rise to the understanding of swallowing of the Sun and the Moon by the snake. When the sun conjoins either node on the ecliptic, the new moon will obscure...