«فَزَحْزَحَتْ شَفَقًا عَشِيَّ سَنَا قَمَرٍ»
She moved an evening twilight from the glow of a moon.
Shafaq is the red twilight after sunset; it evokes the beloved's red veil. Sanā qamar is moonlight, standing for the brightness of the face revealed beneath it.
Removing a veil is transformed into a celestial event: red twilight clears and the moon shines forth. The literary effect comes from expanding an intimate action into a striking image from the sky.