Kartika Poornima
Kartika Poornima (Kartika purnima) is a holy festival, celebrated on the Purnima (full moon) day or the fifteenth lunar day of Kartika (NovemberDecember). It is also known as Tripuri Poornima and Tripurari Poornima. It is sometimes called Deva-Diwali or Deva-Deepawali - the festival of lights of the gods.
Tripuri Poornima or Tripurari Poornima derives its name from Tripurari - the foe of the demon Tripurasura. In some legends of Kartik Poornima, the term is used to denote the three demon sons of Tarakasur. Tripurari is an epithet of god Shiva. Shiva in his form as Tripurantaka ("Killer of Tripurasura") killed Tripurasura on this day. Tripurasura had conquered the whole world and defeated the gods and also created three cities in space, together called "Tripura". The killing of the demon(s) and destruction of his/their cities with a single arrow - by Shiva overjoyed the gods and they declared the day as a festival of illuminations. This day is also called "Dev-Diwali" - the Diwali of the gods. Diwali is the Hindu festival of lights.
Kartik poornima is also the birthday of Matsya, god Vishnu's fish-incarnation (Avatar). It is also the birthday of Vrinda, the personification of the Tulsi plant and of Kartikeya, the god of war and son of Shiva. This day also is considered special for Radha, the lover of Krishna - Vishnu's incarnation. It is believed that Krishna and Radha danced rasa and Krishna worshipped Radha on this day. This day is also dedicated to the pitrs, dead ancestors.
Kartik Poornima is closely associated with Prabodhini Ekadashi which marks the end of Chaturmas, a four-month period when Vishnu is believed to sleep. Prabodhini Ekadashi signifies the awakening of the god. Chaturmas penance ends on this day. Many fairs that begin on Prabodhini Ekadashi end on Kartik Poornima, Kartik Poornima usually being the most important day of the fair. Fairs that conclude on this day include Prabodhini Ekadashi celebrations at Pandharpur and Pushkar Fair. Kartik Poornima is also the last day to perform Tulsi Vivah ceremony that can be performed from Prabodhini Ekadashi.
Also, it is believed that Vishnu, on this day, returns to his abode after completing his stay in Bali. Hence, the day is known as Deva-Diwali.
Veda Vyasa, collected the Vedic Texts of prayer under the Rig Veda, the Vedic texts of rituals under the Yajur Veda, the musical form of the Vedic texts under the Sama Veda and such of the Vedic texts that dispelled dangers and annihilated enemies under the Atharvana Veda.