Gobhilagrihyasutra 2.8.1

2.8.1

jananād yas tṛtīyo jyautsnas, tasya tṛtīyāyāṃ prātaḥ saśiraskaṃ kumāram āplāvyā 'stamite vīte lohitimny añjalikṛtaḥ pito 'patiṣṭhate.

On the third (Tithi) of the third bright fortnight after his birth, in the morning the father has the child washed, including his head, and after sunset, when the evening-red has disappeared, he worships (the moon), holding up his joined hands.