I ran into a problem: the texture for this system has a very low resolution—nothing like what’s shown in the mod's screenshots. I tried everything in the settings, but nothing helped.

Strange. Could you take a screenshot of your graphical settings? I'd like to try reproducing that bug in my game.

I'm looking for potential reasons for your bug. Apparently, depending on graphical setting, factorio might downscale sprites larger than 2048px (our solar system sprite is 2600px wide). If that's the case, we might attempt to reduce the image size and/or use lossless compression to help the game load the picture right.

Good news, after other reports of this bug, we've found the culprit. Better Starmap Background would load its starmap sprite after A&B, overlapping the pulsar with low resolution black pixels.

This has been fixed in 0.3.16. Now, Bellicos's sprite loads after the starmap background.
Bellicos's sprite used to feature a solid black background, so it has been made transparent so you can see the stars behind.