Kartik purnima is a very important Hindu festival that is celebrated on the full moon day of the month of Kartika. This year Kartik purnima happens to be on 14th November. This festival is also known as Tripuri purnima or Tripurari purnima and also Deva Diwali or Deva Deepawali. Kartik purnima is important for a number of reasons to the worshippers of Lord Vishnu. This day happens to be the birthday of the Matsya or fish avatar of Lord Vishnu. It is also the birthday of Vrinda, the personification of the Tulsi plant and also that of Kartikeya, the god of war and the son of Lord Shiva.
This day is also the day when Lord Krishna and Radha Rani performed a special raas leela in the forests of Vrindavan and Lord Krishna worshipped Radha Rani. Hence, Radha Rani is always worshipped on this day and the devotees receive her blessings. Kartik purnima is also closely associated with the most important Prabodhini Ekadashi. Prabodhini Ekadashi marks the end of the period of Chaturmas, the four months during which Lord Vishnu is believed to be asleep. Prabodhini Ekadashi is the day when Lord Vishnu awakens and all Chaturmas penance comes to an end.
There are many spiritual and religious fairs that begin on Prabodhini Ekadashi and end on Kartik Purnima. Kartik Purnima is of course the most important day of the fair. Of these fairs, the most well known are the fairs of Pandharpur and Pushkar. Kartik Purnima also happens to be the last day during which devotees can perform the Tulsi Vivaah ceremony. However, the main reason why Kartik purnima is celebrated with such pomp and grandeur is that on this day Lord Vishnu finally returns to his heavenly abode after finishing his stay at the island of Bali. This is why this day is also known as Deva Diwali or Deva Deepawali.