The presiding deity in the sanctum-sanctorum is Mahavishnu. He is worshipped according to the pooja routines laid down by Adi Sankaracharya and later written formally in the Tantric way by Chennas Narayanan Namboodiri (born in 1427). The Chennas Namboodiris are the hereditary Tantris of the Guruvayur temple. The temple/pooja routines are strictly followed without any compromise. The Tantri is available full time at the Temple to ensure this. The Melsanti (Chief Priest) enters the Sri Kovil (sanctum sanctorum) at 2:30 AM and does not drink even a glass of water up to the completion of noon poojas at 12:30 PM. The Vedic traditions being followed here with absolute perfection and sincerity is the hallmark of the Guruvayur temple. It is important to note here that, even though the shrine is considered to be one of the holiest spots for Vaishnavites, the temple is not a part of the 108 Divya Desams.