Thirupampuram Rahu Ketu Temple History
It is said that many Naga kings, including Adisesha ( Vishnu's couch), Takshaka and Karkotaka worshiped Siva at this place, thus the Lord Siva here called by Thirunageswaram.
Once it happened that, when Vinayaka offering prayers to Lord Siva, Naga which lies around the neck of Lord Siva felt proud as if Vinayaka was worshiping him too, knowing this Lord Siva cursed Naga's family to lose their Spiritual powers.
In order to regain their spiritual powers, Adisesha along with other serpents offered prayers to the Siva Idols which were at the three different places at three different timings. In the early hours, pooja was offered to the Siva Idol at Kudanthai, at noon it was at Thirunageswaram and in the evening it was at Thirupampuram. Lord Siva was pleased with their sincere prayers and blessed them all with their spiritual powers.
Thirupampuram Rahu Ketu Temple
Lord Siva worshiped as Pampunathar and Goddess Parvathi is depicted as Piraisoodi Amman. This temple has one main Gopuram at the front. There is a sacred tree called by Vanni Tree, where couples used to tie ropes and other materials for children. Adhisesha Theertham (Temple tank) which is at the entrance was built by Adhisesha while doing penance here.
Reference Link: http://gotirupati.com/thirupampuram-rahu-ketu-temple/