The poem opens with a single word, "duration," then asks a question: how can we speak of eclipse, worship, value, frenzy? Those four words are huge and abstract. Each points to something overwhelming, whether it's a darkened sun, devotion, worth, or wild excitement. The question suggests that language may be too small or too tidy to hold them.
Then the poem swerves. Instead of an answer, we get "the non-spectrum / of incomprehensible pigeons." It's a funny, odd image. Pigeons are ordinary and a bit scruffy, and here they become something we can't make sense of, something outside any range or scale.
The speaker seems puzzled, maybe a little playful. The mood is quiet and wry, with an edge of mystery. Judging by the jump from grand ideas to birds, the poem hints that the everyday can be just as unreadable as the sublime, and that words often fail at both.