Pitri-Paksha (fortnight of the paternal ancestors) is a 16 lunar-days period in Hindu calender when Hindu pays homage to their ancestors, specially through food offerings.
It is observed from full-moon day of Shukla paksha of Bhadrapada to No-moon day of Krishna paksha of Ashvin Hindi maas.
Throughout Pitri Paksha, everyday non-casual foods like( Bada and Puri) are prepared to offer deceased ancestors.
Pitri-Paksha occurs in Ashvin Krishna Paksha. During this the Sun transits from north celestial sphere to the south.
In Hinduism souls of ancestors reside in Pitriloka, a realm between Heaven and Earth and this is governed by Yama, the god of death.
Prayers and offerings during Pitri Paksha bring upon Moksha(salvation) to ancestors and to the performer.
Along with person’s debt to his Guru and his parents, debt repay of his ancestors by performing rituals in Pitri Paksha is of utmost importance.
Shraddha is performed on pecific lunar day of the Paksha as per on which lunar day parent, grandparent or family member died.
Son(usually eldest) or male relative of the paternal branch of the family has to perform Shraddha.
There is such belief that feeding crow in Pitri-Paksha specifically on the day of Shraddha is considered to be fed directly to the ancestors.