Amavasya Shraddha (Mahalaya Amabasya, Sarva Pitru Amavasya)

Amavasya Tithi Shraddha is done for those deceased family members who died on Amavasya Tithi, Purnima Tithi and Chaturdashi Tithi.

If someone is not able to perform Shraddha on all Tithis then single Shraddha (for all) on this day is enough to appease all deceased souls in the family. If death anniversary of ancestors are not known or forgotten then those Shraddhas can be performed on this Tithi. That's why Amavasya Shraddha is also known as Sarvapitra Moksha Amavasya.

Also Mahalaya Shraddha for those who died on Purnima Tithi is also done on Amavasya Shraddha Tithi and not on Bhadrapada Purnima. Although Bhadrapada Purnima Shraddha falls one day before Pitru Paksha but it is not part of Pitru Paksha. Usually Pitru Paksha starts on the next day of Bhadrapada Purnima Shraddha.

Amavasya Shraddha is also known as Amavas Shraddha. In West Bengal Mahalaya Amavasya marks the beginning of Navratri festivity. It is believed that Goddess Durga was descended on the Earth on this day.

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.