Upakarma or Avani Avittam is a vedic ritual practiced by the Brahmins. Upakarma is conducted once a year during the Shravana maasa, when Brahmins ritually change their Upanayanam (sacred thread) accompanied by relevant Shrautha offerings to the rishis, whom they believe composed the vedic hymns. On the following day, the Gayathri Mantra is recited 1008 or 108 times.
Rig Veda Upakarma is observed on that day of Shravana month which has Shravana nakshathra (spans at least from sunrise to mid day) and falls in the Shukla Paksha. Rig Vedic Brahmins change the sacred thread on that day, irrespective of whether it is a full-moon day (pounami) or not.
