The full moon day of the Karthika Month of the lunar calendar is one of the most auspicious days for a Hindu. Karthika Month is the only month in which both Lord Shiva and Lord Vishnu are worshipped. Karthika Pouranmi or Karthika Purnima is also one of the days when the temples of Lord Shiva and Lord Vishnu are full with the devotees wanting a darshan of their deities.
The other names of Karthika Pournami are Deva Deepawali or Deva Diwali, Tripuri Purnima or Tripurari Purnima.
Kathika Purnima is also clebrated as the day on which Lord Vishnu incarnated as Matsya or Matsyavatram happened on Karthika Purnima. Matsyavatara was to save Manu from the MahaPralaya.
Dev Deepawali or Deva Deepavali
Dev Deepawali is celebrated in Varanasi and other northern parts of India. It is believed that Lord Shiva killed Tripurasura on Karthika Purnima and hence Gods celebrated by lighting diyas. In Varansi all the Ghats are lighted with diyas. It is a visual delight. Not only the Ghats but almost all the houses in Varanasi also decorated with diyas.
Lord Shiva killed the demon Tripurasura on Karthika Purnima and hence the name Tripura Purnima or Tipurari Purnima.
Karthika Purniam is also associated with Prabodini Ekadasi. Prabodini Ekadasi marks the end of the four month long Chaturmas Vrat. A lot of fairs and festivities which begin on Prabodini Ekadasi end on Karthika Purnima.