Vaishnava Dharmashastra 90.14

90.14

prauṣṭhapadyāṃ proṣṭhapadāyuktāyāṃ godānena sarvapāpavinirmukto bhavati ||

If on the full moon day of the month Praushthapada
(or Bhâdrapada) the moon is seen in conjunction with the lunar asterism Uttaraproshthapadâ (or Uttarabhâdrapadâ), and he gives a cow (to a Brâhmana) on that day, he is cleansed from every sin.