Matsyapurana 141.46

141.46

samāgamya lavau dvau tu madhyāhnānnipatanraviḥ
pratipacchuklapakṣasya candramāḥ sūryamaṇḍalāt //

After the Amâvâsyâ day the junction with the Pratipada (first day) lasts for two lavas and this period is known as Kuhû for two letters in the word Kuhu correspond with the two lavas (the duration of Kuhû.) When the Moon is visible on any Amâvâsyâ He unites with the Sun in the afternoon and on the following morning in the Pratipada of the bright fortnight He rises along with the Sun. A difference of a period of two lavas is seen at the noon time between the Sun and the Moon.—44-45.