Karthikai Deepam (Tamil: கார்த்திகை தீபம்) or Karthikai vilakkidu (Tamil: கார்த்திகைத் விளக்கீடு) [ also known as Karthika Deepam(కార్తీక దీపం) in Telugu ] is a Hindu specially Hindu Tamils and Hindu Telugu festival. The festival is observed in every home and every temple, and falls in the month of Kārttikai (mid-November to mid-December) as per Tamil calendar. This occurs on the day when the moon is in conjunction with theconstellation Karthigai (Pleiades) and purnimai. This constellation appears as a group of six stars in the firmament in the shape of a pendant from the ear.
Many legends and lyrical poetry have grown round this star. The six stars are considered in Indian mythology as the six celestial nymphs who reared the six babies in the saravana tank which later were joined together to form the six faced Muruga. He is therefore called Karthikeya, the one brought up by the Karthigai nymphs. Houses and streets are lit up with rows of oil lamps (Deepam) in the evening of the festival day.
Lord Shiva appeared as an endless flame of light before Lord Vishnu and Lord Brahma, who each considered himself supreme and said that the matter could be tested if the two could search for Lord Shiva’s Head and feet. Lord Vishnu took the form of a boar(Sanskrit:Varaha, Tamil:Varahan) and delved deep into the earth, Lord Brahma that of a swan(Sanskrit:Hamsa, Tamil:Annam) and flew towards the skies. Lord Vishnu failed in his search and returned. But Lord Brahma, chancing upon a piece of Thazhambu, a flower, learnt from it that it had been floating down for thirty thousand years from Lord Shiva’s head. He seized upon this and claimed to Lord Shiva that he had seen the other’s top. Lord Siva realized the falsehood and pronounced that there would never be a temple for Lord Brahma in this world. He also interdicted the use of the flower Thazhambu in his worship. Lord Shiva appeared as a flame, this day is called Maha Deepam.