Fourth Day of Pitrupaksha, Fourth Day of Mahalaya Paksha, Fourth Day of Shraddha, Chaturthi Shraddha, Chauth Shraddha
The fourth day of the dark phase or waning phase of the moon of the month of Bhadrapada or Bhadrapada Krishna Paksha Chavithi or Chaturthi as per the lunar calendar is observed as Chaturthi Shraddha. According to north Indian Purnimant Calenders, Chaturthi Shraddha falls in the month of Ashwin.
Chaturthi shraddha as the name suggest is the fourth day of the sacred Mahalaya Paksha which is fifteen day long. Shraddha of the people who have died on the Chavithi or Chaturthi thithi of both Krishna and Sukla paksha is done on Chaturthi Shraddha or Chauth Shraddha. Pinda Daan is done after the Tarpans in the process of Shraddha Karma. Then these Pinda are either immersed in a river and if there is no river are given to the cow as food.
On Chaturthi Shraddha Tarpan and Pinda Daan are done for all the ancestors who have died the previous year irrespective of the Tithi they died. Because of the Bharani Nakshatra Chaturthi Shraddha is also known as Chautha Bharani.
The Shraddha should be performed such that the lunch would take place at the Aparahna Time of the day approximately around 1-2PM.