Shraddh is one of the most significant time to remember our ancestors and pray for the departed souls to rest in peace. As per the Hindu calendar , during the time of Pitru Paksha, if you offer prayers and perform certain rituals for your ancestors, you will be blessed by them and their souls will rest in peace. Dwitiya Shraddha falls on the Vidiya thithi of Krishna Paksha of Bhadrapada month or the second day of the waning phase of the moon in the month of Bhadrapada as per the lunar calendar. According to north Indian Purnimant Calenders, Dwitiya Shraddha falls in the month of Ashwin.
In many places, Lord Vishnu is worshipped on this day. Lord Vishnu is the creator of the world and the mankind. It is considered auspicious to perform Pooja for the Lord Vishnu. Lord Vishnu blesses his devotees with a long and happy life and also helps to gain moksha or salvation in the after life.
Dwitiya Shraddha is done for those deceased family members who died on Dwitiya Tithi, including both Shukla and Krishna Paksha Dwitiya. Dwitiya Shraddha is also known as Dooj Shraddha. The whole fifteen days are measured auspicious for offering Tarpans to the departed.
Pitru Paksha Shraddhas are Parvan Shraddhas and auspicious time to perform them is either Kutup Muhurat and Rohinaetc. Muhurat after that till Aparahna Kala gets over. Tarpan (तर्पण) is done at the end of the Shraddha. Legend- Ramdevpir-dooj or Ramdevpir-beej, the second day of Shukla paksha of Bhaadra month is celebrated as Birthday of Ramdevji in North-western India.
Tritiya Shraddha is done for those deceased family members who died on Tritiya Tithi, including both Shukla and Krishna Paksha Tritiya.
Tritiya Shraddha is also known as Teej Shraddha.
Pitru Paksha Shraddhas are Parvan Shraddhas(पार्वण श्राद्ध) and auspicious time to perform them is either Kutup Muhurat and Rohina etc. Muhurat after that till Aparahna Kala gets over. Tarpan (तर्पण) is done at the end of the Shraddha.