when I read this poem I thought that it was mostly just describing the painting, and what's happening in it. The poem has 3 stanzas and I think each stanza are describing different things.

When I read the first stanza I can see that it's just like a description of the painting by Van Gogh,  the stanza says that the night boils with eleven stars and I see well in the painting "Starry night" that it does have many stars and it does have eleven stars. Also in the painting I can see a large cypress tree at the left side, and it fills like the whole half of the painting, and the tree is also described in the first stanza of the poem.
I think the second and last stanza of the poem is about Van Gogh and how he felt because there is this line "The unseen serpent swallows the stars" and I think what he means that all the happiness, which I think is represented by the stars are swallowed up, and he just is feeling sad. In the last stanza there is this line that says " to split from my life" I feel like it means that Van Gogh wants to end life quickly and it just gives a feeling of death.