Hopkins does not so much describe the night sky as shout at it. The first line is a string of orders, "Look at the stars! look, look up at the skies!", and the command returns seven times before the sonnet ends. It is the voice of someone who has seen something astonishing and cannot wait for you to catch up. But the poem does not stop at astonishment. Its central idea is that the beauty of the stars is an outer wall: dazzling in itself, but also the surface of something larger, the heaven where Christ, his mother and the saints are gathered. Hopkins was a Jesuit priest, and the closing image makes that faith the point of the whole poem.
The first eight lines cannot settle on one comparison for the stars, so they try several. They are "fire-folk sitting in the air", then a city of "bright boroughs" and "circle-citadels". Then the view drops to the woods, where "diamond delves" suggests jewel mines glimpsed between branches, and "elves'-eyes" adds something small, watchful and slightly uncanny. Next come "grey lawns cold where gold, where quickgold lies", and "quick" here means "living", so the gold seems to stir. Then come wind-flipped trees flashing pale leaves and "flake-doves sent floating forth at a farmyard scare". Each image is knocked aside by the next. The cosmic is repeatedly pulled down into the homely: lawns, orchards, a farmyard. The stars are not remote lights but part of an ordinary countryside that has suddenly caught fire.
The sound matches the crowding of images. Consonants pile up ("Wind-beat whitebeam", "Flake-doves sent floating forth at a farmyard scare"), and Hopkins fuses words into compounds such as "quickgold" and "circle-citadels", so the lines are dense and need slow reading. The heavy stresses sit close together, which makes the lines feel crammed with light. The octave's rhyme scheme is the traditional abba abba of the Petrarchan sonnet. Its rhymes keep looping back, as though the poem is circling the sky and finding the same thing from every side.
At line eight comes a sigh: "Ah well!" The mood changes from wonder to reckoning, and the language moves to the marketplace: "it is all a purchase, all is a prize. / Buy then! bid then!" The reader, still dazzled, expects a price in coins. The answer deflates that expectation: "Prayer, patience, aims, vows." Beauty can be had by looking, but the heaven it points to has to be earned through spiritual effort. Both "purchase" and "prize" suggest something worth striving for, and the dash-interrupted question "—What?—" makes the poem sound like a conversation, as if Hopkins is bargaining aloud.
The sestet moves to spring. The stars become "May-mess, like on orchard boughs" and "March-bloom, like on mealed-with-yellow sallows". The sallows are willows, and "mealed" suggests catkins dusted like something floured. This is a gentler, more fragile picture than the fire and diamonds of the octave. Blossom is a promise of fruit, so the imagery looks ahead to the final harvest metaphor. The stars, we are told, "are indeed the barn". They are the outside of a building, and inside, "withindoors house / The shocks", the stacked sheaves of the crop. The "piece-bright paling", a fence made of bright fragments, "shuts the spouse / Christ home". The rhymes tie the idea together: "house" with "spouse", and "sallows" with "hallows", so that the willow catkins of earth are echoed by the saints of heaven in the last word.
That last line is worth hearing aloud. The name "Christ" appears twice in quick succession, and the line then widens to "his mother and all his hallows", ending in a crowd of saints, which is exactly where a poem about looking up should end.
The poem's significance lies in how it makes language as crowded and physical as what it describes, and in its unusual idea of nature. The stars do not distract from faith. They are the bright palings of a fence, and the poem asks the reader to look through the gaps. It is also playful, since heaven turns out to be a well-stocked farm, and that humour keeps the sonnet from feeling like a sermon.