Bhagavatapurana 3.7.33

3.7.33

śrāddhasya ca vidhiṃ brahman pit-ṇāṃ sargam eva ca /
graha-nakṣatra-tārāṇāṃ kālāvayava-saṃsthitim //

33. How Sraddha (श्राद्ध) is to be performed, O Brahman, the origin of the Pitris, of the planets, nakshatras and stars, and the arrangement of the divisions of Time;