I know a fair bit of constellations, perhaps enough to navigate by on a clear night. I would just assume that the spiral galaxy would be Andromeda, the furthest thing you can see with the naked eye. But then again, none of this is done with a naked eye so more spiral galaxies might appear visible here.
I agreee, it's awesome.Knowing the little you explained how it was done, I think I would most accurately call it an digital image mosaic if anything.