I'm looking mostly for the purposes of sending and receiving astropathic messages (p.163).

lurkeroutthere said:

The Koronus Expanse is a Sector, same as Calixis.

"Expanse" and "Sector" denotes the same space. The only difference is that Expanse applies to a sector nor incorporated to the Imperium yet.

Ah ok, that's what I thought it might be but I figured it was possible the expanse might be bigger or smaller based on once it was actually settled it would be broken into regular administrative chunks. After all it's not like undiscovered areas of space come in easily formatable territories. Thanks for the answer.