Vaikunta Chaturdasi is observed on the 14th day of the Shukla Paksha or waxing phase of moon in Kartik Month

Vaikunta Chaturdasi is observed on the 14th day of the Shukla Paksha or waxing phase of moon in Kartik Month. The popular belief is that on Vaikunta Chaturdasi day Srihari Vishnu received the Sudarshana Chakra from Lord Shiva. This day is auspicious for both Sri Vishnu and Lord Shiva. They are worshipped ESP in Varanasi, Rishikesh, Gaya and Maharashtra. Fast is observed on this day and lord Shri Narayana and Shiva worshipped.

The Legend has it that Lord Vishnu decided to visit Lord Shiva who was residing at Kashi. Lord Vishnu collected 1000 lotus flowers from Manasarovar to offer it on the Shivalingam at Kashi by reciting the 1000 names of Shiva. After collecting the flowers from Manasarovar in the Himalayas, Lord Vishnu reached Kashi and was warmly welcomed by Lord Shiva. Lord Vishnu then began to offer the flowers one by one to the Shivalingam at Kashi. He offered one lotus flower on chanting each name of Shiva. Lord Vishnu was fully absorbed in his worship when Shiva decided to test Him and removed one lotus flower that Lord Vishnu had brought and hid it.
Lord Vishnu chanted the 1000th name of Shiva and when he looked for the 1000th lotus flower it was missing. Lord Vishnu realised that He is known to his devotees as Kamalakanan – the lotus eyed. So he offered one of his eyes instead of the last Lotus, to Shiva. Shiva was moved by this devotion of Lord Vishnu and immediately hugged Vishnu and thus restoring his eye. Lord Shiva then presented the Sudarshana Chakra to Vishnu to fight evil. Lord Vishnu and Shiva are worshipped on the day and people observe Vaikuntha Chaturdashi Upvas.

On this day Shri Vishnu is given a special place of honour in the sanctum of Kashi Vishwanath temple, Varanasi. ‪The temple is described as Vaikuntha on this day. Both the deities are ritually worshipped as though they are worshipping each other. Shri Vishnu offers tulsi (holy basil) leaves (traditionally used in Vishnu worship) to Shiva, and Shiva in turn offers Bael leaves (traditionally offered to Shiva) to Vishnu, which is taboo otherwise, to each other. Devotees start the pujas after taking baths, fasting for the whole day, and offering akshat ( turmeric mixed rice), sandalwood (Chandan) paste, sacred water of the Ganges, flowers, incense and camphor to both the deities. Then they offer lighted deeps (earthen lamps) and batti (cotton wick) as a special offering for the day. At Lord shivas the Grishneshwar temple Maharashtra also, Shri Vishnu is offered Bael leaves and Shiva is offered Tulsi leaves. It is considered to portray the union of Vishnu and Shiva.
Jai Shri HariHar ~ Jai Shri ShankarNarayana ~ Har Har Mahadev Shambhu Kashi Vishwanath Gange!!!