Assuming we abide by Traveller's 2D space maps... And the hex numbering system it uses... And that each system is named for its primary inhabited planet... And that each star is conveniently at the center of each hex... And we'll say planets always orbit in perfect circles...

100 concentric circles (bands) radiate from the namesake star, which are a standardized width, which I won't specify, because hey it's just a sci fi game.

But, the bands are based on the largest known solar system when the scale was invented.

So, a compact solar system's furthest planet might only be at the 62nd band.

Then measure each circle in degrees

<aside> ❗ WAIT! WAIT! WAIT! Wouldn't it be easier if it were a percentage? The furthest planet is at .100 A planet halfway between the sun and the furthest planet would be at .50 And what about a system larger than the standardized system can handle? (although, I guess it just expands with it - .109, .136, etc..)

</aside>

Felbrigg Subsector covers hex numbers 4601-5309

Nelius System is at 5105

Therefore, Planet Nelius could be 5105.44 ... Because it's the 3rd or maybe 4th planet around the star

Planet Enton in the Nelius System might be 5105.79 ... Because it's the furthest planet from the star

Or, if you know where it is in its rotation, you might have (temporary) exact coordinates... ... Planet Enton 5105.79.106

So, CommTact gets a signal from coordinates 5105.79.106

Sends that info to NavHelm

NavHelm says it's the planet Enton

And he knows that because it matches to that celestial body in the maps/database.

But, really he'd only need the first two sets of numbers because orbital objects would be cataloged by what band they're orbit A is in from the star.