I was looking for Sirius Sector in Google Sky, and it wasn't surprising that I didn't find it. As much as I know, Sirius Sector is just a collection of randomally chosen nebulas and clouds from our galaxy that look good together.
I've found the Walker nebula (Omega, I don't remember the real life name), The Rheinland Cloud (Eagle Nebula), The Bretonia Cloud (So many possibilities...), and the Barrier (which is a whole separate galaxy). The rest (Crow - Kusari, and Edge - Omicron) are fantasy, or some different mix.
I know many have spoken about this already, but I just wanted to say it myself 