Srimad-Bhagavatam: Canto 8 - Chapter 1 - Verse 26


Sanskrit:

शिरस्त्वमरतां नीतमजो ग्रहमचीक्लृपत् ।यस्तु पर्वणि चन्द्रार्कावभिधावति वैरधी: ॥ २६ ॥

ITRANS:

śiras tv amaratāṁ nītamajo graham acīkḷpatyas tu parvaṇi candrārkāvabhidhāvati vaira-dhīḥ

Translation:

Rāhu’s head, however, having been touched by the nectar, became immortal. Thus Lord Brahmā accepted Rāhu’s head as one of the planets. Since Rāhu is an eternal enemy of the moon and the sun, he always tries to attack them on the nights of the full moon and the dark moon.

Purport:

Since Rāhu had become immortal, Lord Brahmā accepted him as one of the grahas, or planets, like the moon and the sun. Rāhu, however, being an eternal enemy of the moon and sun, attacks them periodically during the nights of the full moon and the dark moon.