Canto 2 -
Ayodhyā-kāṇḍa
Chapter 40: Rāma Departs from Ayodhyā
Text 2.40.31

पिता हि राजा काकुत्स्थः श्रीमान्सन्नस्तदाभवत्।
परिपूर्णः शशी काले ग्रहेणोपप्लुतो यथा॥

pitā hi rājā kākutsthaḥ śrīmān sannas tadābhavat
paripūrṇaḥ śaśī kāle graheṇopapluto yathā

pitā hi = Rāma’s father; rājā = king; kākutsthaḥ = descending from Kakutstha; śrīmān = a prosperous; sannaḥ = deprived of his prowess; tadā = then; abhavat = became; paripūrṇaḥ = the full; śaśī = moon; kāle = at the time [of a lunar eclipse]; graheṇa = by Rāhu; upaplutaḥ = is overtaken; yathā = just as.

Rāma’s father, a prosperous king descending from Kakutstha, then became deprived of his prowess just as the full moon is overtaken by Rāhu at the time [of a lunar eclipse].