Today, 18 July 2012 is Aadi Amavasai in Tamil Nadu. The main ritual of Aadi Amavasai is Pithru Tharpanam vidhi. Offering shraddha rituals to dead ancestors (forefathers) is considered highly meritorious.
Aadi Amavasai begins at 9.38 AM on 18 July and ends at 10.20 AM on 19 July.
It coincides with similar ritual in Kerala – Karkidaka Vavubali.
Aadi Masam is considered inauspicious for any auspicious event but for Devata Pujas, vratas and Pithru Tharpanams it is the best period.