Valmiki Ramayana Kishkindha Kanda Sarga 28 Shloka 13

मन्मथवताम् for the lovers, हिताः favourable, प्रतिहताः blocked, नष्टग्रहनिशाकराः Moon or planets seized to appear, इमाः this, ताः दिशः directions, घनैः with dense clouds, अनुलिप्ता इव as if smeared.

'Smeared as it were with dense clouds and therefore blocked the directions in which planets including the Moon cease to appear are favourable to lovers. The Moon is said to accenuate the pangs of separation from one's ladylove. Hence the quarters in which the Moon and the stars are hidden by clouds, have been favourable to the lovelorn.