each dash starting from the left is a system level, a - means the station won't appear there, a r is rare, a c is common, a u is uncommon, v is veryrare.
so in your example it would not appear until level 3 systems, and then it would be rare, the next level it would commonly appear, and the next it would be uncommon, then rare again, and then never show up after
Not exactly- Sanctuary (CD) is located about the middle of level 5 nodes,
Jiang's (C9) is the last level 6 system
Eta Ceti (EC) lv7 and Point Juno (PJ) lv8 similarly the last systems of their level.
I just was looking at the topology, don't think I knew that! <StarSystemTopology> that is.