The main rituals in connection with the Somayagom began following the churning of the fire (arani-kadayal or agni-manthana) on Tuesday evening.
The Somayagom, organised by the Vedasara Charitable Trust, began at Elakolloor, near Konni, on Monday.
The formal inauguration of the vedic ritual was done by Chief Minister Oommen Chandy on Friday afternoon.
The Yajamanan of the Somayagom, Keezhe Perumbadappu Vaidikan Hrishikesan Namboodiri, and his wife, Sreedevi Antharjanam, entered the Yajnasala in the evening.
The Yajamanan accorded a customary reception to the Ritwiks in traditional style. The churning of fire took place after that.
Perumbadappu Vaidikan, Sankaranarayanan Adithirippad and Kavapramarathu Sankaranarayanan Adithirippad are the chief tantriks at the yajnom.
Thottom Sivasankaran Namboodiri is the chief coordinator of the Somayagom, which will come to a close on April 26.
This is the first time a Somayagom is being organised in Central Travancore, according to Swami Prabhakarananda Saraswathi, the Yajnacharya of the vedic ritual.