I really like it, but I'm not sure what I think of all the "thou"s. Maybe try mixing it up a bit more with "thee" and "thine" if that's the style you're going for. Example:

"If thine stars are not there after nightfall"

That's actually gramatically correct. Plus it plays the "i" in "thine" off of the "i" in "night". "Thou stars" doesn't sound quite right.

Otherwise, I really liked this. It's got good atmosphere, and it's ambiguous, which is one of my favorite writing styles. I prefer the message in a poem/song to be difficult to figure out, rather than bludgeoning the reader over the head with it. Great job!