What is it?
Dex says Kamino is about 12 parsecs (3 dozens ly iirc) outside of it, southwards or something like that.
In AOTC it's possible that it looks like a small galaxy. But I guess it should be a very small one. Minuscule, in fact.
The wookieepedia page makes things even more complicated.
http://starwars.wikia.com/wiki/Rishi_Maze
Notably with Chee's statement.
Looks more like a spiraling tight cluster of stars that counts a few arms at best, close to the main galaxy.