Tarpan is a significant ritual performed during the Pitr Paksha, a 16-lunar day period in the Hindu calendar dedicated to paying homage to one's ancestors (Pitrs). This period usually falls in the month of Bhadrapada, following the full moon day (Purnima), and ends on the new moon day known as Sarva Pitru Amavasya or Mahalaya Amavasya.
Pitr Paksha and the Tarpan ritual emphasize the continuity of family and the importance of honoring ancestors. It is believed that neglecting these rituals could lead to dissatisfaction among the ancestors, which might bring misfortune to the family.
This period is also marked by charity and feeding Brahmins and the needy, as these acts are considered meritorious and beneficial for the souls of the ancestors.