When the amirtham emerged, Lord Vishnu in the guise of Mohini was distributing the amirtham only to the devas. He was worried that the evil deeds of the asuras will increase multifold if they consumed amirtham. Realizing this, one of the asuraas with the help of the asura Guru Sukrachariyar, took the form of a deva and consumed the nectar. Suryan and Cha dran who noticed this, complained to Lord Narayana. In anger, Lord Narayana hit the asura on the head with the spoon in his hand. The head was cut off and fell on the ground.
But because the asura had consumed amirtham, his head and body continued to live. The body of a snake got attached to the head to become Rahu Bhagavan. Rahu prayed to Lord Vishnu (Narayan) and got the position of a Sayagraham. Rahu takes his revenge on Suryan and Chandra, whether he gets a chance by devouring them. This is commonly called a s eclipse (Grahanam). Rahu is represented on a 'Simhasana' or a silver chariot drawn by eight horses. According to some it possesses four arms, three of which bear 'Khadga', 'Khetaka', and 'Sula' and in Varada pose and sometimes he possesses two arms carrying a book.
Benefits of Worshipping:The person who come to visit Thirunageswaram Rahu Sthalam(Rahu planet) they will find relief from naga dosham, kala sharpa dosham, vivaha dosham(marriage), mental disorders, puthra dosham, nervous and leprosy problems. To come out from all these problems the person praying to Rahu at this sthala helps rids from these factors and also saves the person from all poisonous life forms.
Things of Worshipping:Day : Saturday
Donation : Black Urad Dhal, Seven Types of Grain (Wheat, Rice, Sesame, Moong, Millet, Savan, Gram Cereal), Black Cloth, Gomed, Snake made of Gold, Salt, Coconut, Shoe, Sword, Feeding Snakes
Homa/Havan : Wood From Harit Duba Tree
Medicinal Bath : Dear Musk, Elephant Musk, Doorva (Millet Grass), Leaves of Wood Apple
Flower : Mantharai
Cloth : Block Cloth
Prasatham (Food) : Rice mixed with Black Urad Dhal powder.