The poem imagines the full moon as a huge eye that has slowly opened over two weeks, and it asks a half-joking, half-serious question: how are you supposed to sleep under a gaze that never wavers? The speaker seems wakeful, a little unnerved, and also a bit amused. The moon is "round as an infant," which makes it look innocent, but it is also "indifferent as a cane toad," a blunt, unglamorous comparison that takes the romance out of it.
The middle of the poem widens out. The moon pays no attention to a planetary conjunction, and cares even less about the possible end of life on earth. Its calm is total, and a little chilling. The last lines turn inward. The speaker has one eye on the moon, while "the other eye / now dreams storms." The mood is restless and uneasy: the mind drifts toward disaster even as the sky stays serenely still.