I like this idea a lot - it's a much more simple idea than trying to work out angles or co-ordinates, etc and works well with my overlay of the lighthouses;
https://i.imgur.com/s1IyKaI.png
It also allows us to use the tools we have already -galaxy map and our eyes
So I'm going to search on C22-17 A 3 for a similar crater pattern.
Just a brain fart (working so don't have time to explore deeper just yet), but what if the Relic tower that corresponds to D11-102 (site of ruins) is placed at the smaller circle in a purposeful location. At first, casual glance it seems to me that the geometric features of that circle could be showing how the relic tower relates to the planet it's on. Therefore, be extension other features of the ruins could be relating to whereabouts in the other systems we might find more ruins.
I know this is kinda of repeating what has been said many times over, but I've not seen a pic as clear as that one previously and the line through the small circle put me in mind of the planet's poles and the ruin's location relative to them, or something...