It is an important custom of the temple before the flag is hoisted. It is an offering by the Devaswom, Rulers and the Bhaktas of Vaikkathappan and a special tribute to Him. On that day the Sribali is brought on an elephant in a grand procession. Recital of Vedas, special Abhishekas, Pratal and Vilakku are other main rituals. The Main Sandhya Velas are Mukha Sandhya Vela, Pully Sandhya Vela, Perumpadappu Sandhya Vela and Samooha Sandhya Vela. Some are conducted only nominally nowadays. The Chief Sandhya Vela is done by the Rajas of Ettumannoor, Thekkumkoor, Ambalapuzha and Thiruvalla and are performed in four days. It starts from the Revathy and ends on Karthika of the Thulam month in Malayalam and it is the first among the Sandhya Velas.
After attaching the coastal areas of Alappuzha and Cherthala the Maharaja of Tranvancore Sri. Marthanda Varma started the next Sandhya Vela. The interest of salary arrears of the dead soldiers in that war is used for Sandhya Vela. It is done on alternate days every year. Now the Mukha Sandhya Vela and Pulli Sandhya Vela are looked after by the Devaswom Board after the rule of the Maharajas has ended. The Perumpadappu Sandhya Vela was done by the heads of the Perumpadappu Swaroopam – the Kochi Rajas in Vaikom Temple. They used to keep a full measure of rice every day before their meals. That rice was carried to the temple and given as Pratal every year on the Sandhya Vela day.
They used to bring each and every article for the Pratal and Sandhya Vela and it was a notable aspect of this Sandhya Vela. They have dug even a well for the same purpose in the Esana Cone (north-east corner) of the feeding house. This Sandhya Vela was also discontinued because of the differences between the rulers of Travancore and Cochin. We could see the deserted well today, reminding us the bad and wicked antics of the erstwhile rulers.
The people of the place performed separate Sandhya Velas on separate days. That is called the Samooha Sandhya Vela. The communities of the Virada Tamil Viswa Brahma Samooha (Gold Smiths), Arya Samooha, the Vaikom Samooha, Telungu Samooha and the Vadayar Samooha are the main groups who conduct this Sandhya Vela.
The Goldsmiths of Viswakarma Samudaya inhabit here in thiry six and half desha. They send an annual tribute to their Swami in Thirunelveli. Their Swami insisted to use the amounts thus collected as a tribute to Vaikkathappan. So this Sandhya Vela was started by that amount. It is conducted on the Sukla Paksha Navami before the flag hoisting.
The Arya Samooha, Vaikom Samooha, Telungu Samooha, Vadayar Samooha are mainly the group of Tamil Brahmins. The Vaikom Samooha used to consider Vaikkathappan as their first member, Udayanapurathappan as the second member, the third and fourth members being Melsanthy, Thanthries and other temple employees. They are more in number and are more powerful. The first Sandhya Vela of the Brahmins performed on Sukla Paksha Chathurthy in Malayalam month of Thulam by Arya Samooha,* a section of Vaikom Samooha. On alternate days Vaikom Samooha, Telungu Samooha and lastly Vadayar Samooha observed Sandhya Velas. If there are more days for the flag hoisting after the Sandhya Vela the responsibility to fill the gap is with the Vadayar Samooha.
Offering of a single coin (Otta Panam Vaikkal) is a special feature of the Sandhya Vela of the Brahmins. In the evening lamps are lit in Belikalpura and members of the community come forward and each offer a coin on a cloth spread on the floor. The custom is that the coins are tied together without counting and opened in front of all the community on the next day in noon and counted and handed over to the treasurer of the community.
When there is Pratal in the temple the right and duties to do the work of cooking in the big kitchen goes to Mutus Namboothiri. In like manner, cooking and preparation 
of curry etc. go to the Brahmin community. The preparation of large items, small items, arranging of plantain leafs, distribution of water and rice are divided among all the Samooham. The supervision is done by each Samooham daily in rotation to make the things easy. The oil needed for the Sandhya Vela of the Vaikom Samooha is brought by the Cherthala Samooha and the rice by Mankompu and Velinad areas. While doing Pratal in Udayanapuram Temple the same rules and rights are kept.
As a reward for the old help, the right to offer the first mite still remains with the Karukayil Kaimal coming on a Palanquin. It is known as the Valiya Kanikka in connection with Ashtami festival.