Other than Centauri, Sol, and Sirius, obviously. Maybe specific to Eternity Port, though.
Possible solution:
Rather than uncovering systems when the player finds a stargate and then drawing connections between known systems, instead uncover a connection between the current system and the system linked to by the stargate, and then reveal all systems currently attached to something else by a connection.
Not specific to Eternity Port. Attaching an example from an SotP/CC game, with a save file.
This might be caused by loading a save that was created or last played in an earlier version of the game.
Fixed in 1.7 Alpha 2. The bug was caused by nav beacons. Nav beacons scan the surrounding area when they are created. Since all systems are created at the start, all beacons will scan. If a stargate happens to be near a beacon, then it gets scanned, which means its node will show up.
I fixed this by moving the scanning code to when the player enters a system.