I love it when someone tries to sound all expert and superior, then gets it completely wrong and just looks stupid.
Agreed with Laz here. Sirius in the game is not actually apart of any real life system (I had to look it up on the main Freelancer forums just now) and a majority of its map is based off of real life nebulas and others swen together.
Regardless of how you look at it, The Sirius sector could be on the other end of the galaxy from Sol or just one light year away and no one would know because, as said, the Sirius Sector is a fictional location, just as most locations in Chris Roberts games are (Save Star Commander which was Sol)
Even Canis Major has barely under 15 stars and is spread out wide, the nearest cluster being Canis Majoris Star Cluster which, in of itself, Sirius is not even apart of to begin with. That said, the original star map is just a hashed together system of existing nebulas (At least thats what they've said on the forums by looking it over)
At the end, we don't know where the Sirius sector really is, anyone could put it anywhere in the galaxy, the wiki here says its in the Orions Belt in this galaxy, Crossfire says its near the Canis Majoris star cluster, no one truly knows where Chris based this games location from