Manava Dharmashastra 2.30

2.30

nāmadheyaṃ daśamyāṃ tu dvādaśyāṃ vāsya kārayet
puṇye tithau muhūrte vā nakṣatre vā guṇānvite //

But let (the father perform or) cause to be performed the Namadheya (the rite of naming the child), on the tenth or twelfth (day after birth), or on a lucky lunar day, in a lucky muhurta, under an auspicious constellation.