RAHU-KETU in Indian astrology

"News:- Surya Grahan 2011: New Year Starts with Solar Eclipse Today
Surya Grahan 2011 - The New Year starts with a partial Solar eclipse that can be watched today, the 4th January, 2011 from the northern part of the country besides Europe, the Arabian peninsula, North Africa and Western Asia.

Retired Professor of the Indian Institute of Astro Physics, R C Kapoor said, the partial Solar eclipse will starts in at 12.10 pm and end at 4.30 pm on January, 2011.

Mr Kapoor said, in India, the eastern fringe of the penumbral shadow of the Moon passes over Kutch, parts of Gujarat, Rajasthan, Haryana, UP, Delhi, Punjab, Uttarakhand, Himachal Pradesh and Jammu and Kashmir. In Delhi, the eclipse will begin at 3.11 pm and will end at 3:52 pm."

As per mythological stories, Solar Eclipse happens when Rahu swallows Sun. As Rahu has "head only" eclipse ends when Sun comes out through throat part.

According to legend,(retold in many puranas)the demon by name Swarbhanu stealthily got into the midst of gods and had a share of nectar which was capable of making the eater immortal. This was found out by the Sun and the Moon who brought it to the notice of Vishnu. Vishnu cut the head of the demon as an act of reprimand,which however resulted in the head becoming Rahu (the head with the body of the snake)and the body becoming Ketu (the body with the snake’s head).

This is how the birth of Rahu and Ketu is explained in scriptures.

What is really Rahu - Ketu ?
Take a bucket full of water and consider the level of water as the plane where the Earth circles around the Sun. Take a dinner plate and mark the centre of it as Earth - circular edge is the orbit of the Moon and the surface of the plate is the plane Moon circles around the Earth. Now dip the plate in to the water in a slight inclined position (23°) till the centre of the plate touches water level. Mark the two points where edge of the plate touches water level; these two points are Rahu - Ketu described in Indian astrology. Eclipses can happen only when Moon is at any one of that two points and it is a Solar Eclipse on a new-moon day and Lunar Eclipse on a full moon day . You can visualise that Rahu - Ketu will be always in 180° when viewed from the Earth and both(Rahu-Ketu) cannot be liberated. That's why it is considered as "one" in above stories. Indian Rishi's had great knowledge of the things happening in the universe. And it was acquired by observation only - with out any advanced instruments of the modern world.