Rahu was the son of Asura king viprasithi and queen Simmigai. When the Asura prince Rahu went to the feast following the churning of elixir from the ocean of milk he learnt the subterfuge which Lord Vishnu, in the guise of a bewitching maid, practiced upon the Asuras; Lord Vishnu was distributing the elixir only among the Devas and was denying Asuras. Rahu immediately took the form of a Deva and stood mingle among them. Lord Vishnu had given a spoon of the elixir which Rahu had first taken in when the lord divined that this was an Asura. Upon which knowledge the lord hit him on the head with the ladle he had on hand, sundering Rahu’s head from the trunk. Rahu’s head grew into a snake tail and the trunk grew into a snake’s hood and was called Kethu.
In the zodiac, Rahu and Ketu are always at an angle of 180 degrees and move counter clockwise. They are shadow planets but have immense influence on human life.
Rahu rides upon a goat. He is positioned towards the Southwest direction. He is amenable to the flower Mandharai, the grain of Ulundu and the leaf of Arugu. His form is that of a dark snake. He has eight horses pulling his chariot. His face resembles that of a Lion, and he has four hands. His consort is Simhi.
The period of Rahu’s influence is 18 years. Rahu is the Lord of Wisdom. One should worship Nagarajan or mother Durga, wear the gemstone, and donate silver snake or ulundu and worship at the shrine of Rahu for the curse of fear caused by one’s enemies. Rahu will gift one with life akin to a king.
One enters the temple of Naganathaswamy through the beautiful arch at the entrance. The temple of the tower is five tiered. One goes past many shops selling coconuts and flowers and choultries and wedding halls built enroute. In the space inside the temple tower is the shrine of Nritha Ganapathy and Nandhi. Suriya theertham is to the left. Mazha porutha Vinayagar is also to the left. North of the tower is the hall of hundred pillars and the North Tower.
Inside the second tower is the perambulatory square in which there is the sanctum of Rahu with consorts Simhi and Chitraleka. There is enough space for about a hundred people to sit and pray to Rahu Bhagvan. Devotees offer milk, hymns, and silver snake to this lord of wisdom. It is a sight to behold the milk turn blue as it floes over the dark stone statue of Rahu.
In the front hall there is evidence that Chekkizhar maintained he temple in good state. The lamps are lit before the copper snake figurines in this wall. There also the images of Chekkizhar, his mother and younger brother which are worshipped. In the third perambulatory square are the sanctum of the sixty three saints, vinayagar, Murugar, Lakshmi and four saints of Saivism. Natarajar is also to be prayed at in his shrine.
Naganathaperumal who is the reigning diety of this temple is in the inner sanctum showering grace in the form of Linga. To his left is the shrine of Prayyani Nuthalal, in the outer circumambulatory square. The shrine of Girikujambal is at the northern side. The holy mother is of an aspect which is manifested as the power of desire, power of the creation and the power of the wisdom.