History of Dharmashastra (Ancient and Mediaeval Religious and Civil Law in India) v3.c41.4.4

v3.c41.4.4

The month of Śrāvaṇa being fixed upon, the best day therein would be the full moon (Soma in another sense being the king of brāhmaṇas). If any other day in Śrāvaṇa was to be chosen then the day on which the moon was in Hasta would be the best, which would ordinarily be the 5th of the bright half (of Śrāvaṇa). As the Paurṇamāsī of that month was called Śrāvaṇī owing to the moon's conjunction with the Śravaṇa nakṣatra (which conjunction usually takes place on that day) the Śravaṇa nakṣatra came to be associated with the starting of the annual session of Vedic studies. But that the Śravaṇa nakṣatra by itself had no direct connection with upākarma is clear from the fact that several sūtras do not mention it at all. The Gobhila and Khādira gṛ. do not accept the full moon day of Śrāvaṇa (but of Bhādrapada and the Hasta nakṣatra) as the proper time for upākarma.