Socks1000

Chosen answer: It's a galaxy. Given the distance that the fleet would have to be away from it in order to see the whole thing like that, it seem unlikely that it's intended to be the galaxy that the saga takes place in, but another one that's relatively close to it.

Tailkinker

Answer: It is the Star Wars galaxy. Haven was the codename of the Rebel Alliance's predetermined rendezvous point far beyond the Galactic Rim, where the Alliance Fleet regrouped after the Rebellion's defeat at the Battle of Hoth in 3 ABY. The rendezvous point lay near the coordinates 2.427 by 3.886 by 673.52 above the galactic plane.