I just started playing this great game fairly recently and was bothered by how difficult it was to see small ships and certain types of asteroids on the default background starfield.
All you need to do is replace the Starmap.bmp file in .\Pictures\Systems\800X600 (if you play at 800x600) or .\Pictures\Systems\1024X768 (if you play at 1024x768 or above) subdirectory with a solid black bitmap, 490x490 for the 800X600 directory or 660x660 for the 1024X768 directory. Don't forget to back up the original Starmap.bmp file if you want to be able to revert back. If anyone would like, I could send the appropriate replacement files to someone who hosts a web page with mods, but they're simple enough to create even for a novice with MS Paint.
I'm sure I'm not the first to figure out or do this, but I did a search of the forum and didn't see anyone else mention it at all, so I figured I'd post to help out anyone with the same issue. In my case, it reduced eye strain when playing for long periods (and how can anyone play this game WITHOUT it turning into a long session?
) and helped a LOT in viewing small asteroid belts and escort ships.