I could imagine they are maybe indicators for stars in a certain star constellation. Delta is also referring to the third to fifth brightest star in such a constellation....3...what a coincidence? Maybe this system with the Ruins is the Delta-System.
I find that possible because 1) the location of the pillars and 2) that you can see them from very far away.
Of course they can have multiple purposes.
And another thought: I think at one point we have to stop saying "this COULD BE a stone I have to turn around" but "This IS a stone I have to turn around" If nothing is underneath it, it's fine. But, if I'm not mistaken, there are not many investigations going on outside the ruins, or not?
Well, here is the rub : the ruins are not fixed relative to the sky, so the pillars being pointer is possible, but it may be only once every 6.9dy, and then I guess that there are many stars that would "fit the bill" so to speak.
I'm trying to imagine a way to use this idea to reduce the search time compared to a dumb brute force approach, and so far I fail.
1) each tower points at a circle on the sky. Since all the towers are close-by (in the sense that the distance between them is << than the planet radius) it's really only one circle.
2) add in uncertainty, and we have a high number of stars. This would be fine if there where a way to go from sky map to galaxy map, but there is not. (you cannot point at a start and just select...). This makes determining which stars in this circle corresponds to which systems in the gal map rather... tricky.
3) then, we still don't have any idea of the distance...
I *do* think that the best way to go is working toward finding new ruins, and that the clue we get about the network following a geometrical pattern is an important clue in that regard.
What I'm saying is that without an additional clue, this is rather tricky and prone to tinfoil runaway. (Like : say we suppose the pattern is made of triangles, and it's made of squares lol)*
*regular tillings only allow for triangles, exagons and squares. (though if FD went extra nuts could use penrose tillings and then lol)
My experience with the UP is that before solving the puzzle, one must understand what the pieces are. So far, it's unclear to me what the pieces are.
Anyway, the site latitude is ~-30°, so the sky circle has a ~120° opening (i.e. not a great circle).
And then there are the 5 pillars markings that so far no one (as far as I know) has been able to figure out. Might be a clue.