This image not only works on M1A1 but can also easily be used with the official Marathon 1 by following these steps:
1) If on Mac: Right click on the Marathon app and select "show package contents" and navigate to /Contents/Resources/DataFiles/Plugins. If on Windows or Linux: go to your Marathon 1 plugin folder.
2) Then find the TTEP plugin and open it's Collections folder. You should see sub folders with various numbers for names.
3) unzip the starscape.zip then make 3 copies of the starscape.dds, rename each "04.dds", "24.dds", and "21.dds".
4) Replace image "04.dds" inside folder 02. Replace image "24.dds" inside folder 17. And finally replace image "21.dds" inside folder 18.
5) Enjoy the better graphics! This starscape image is significantly better than the one included in TTEP.
2048x1080: An improvement upon the original M1A1 "stars" background image, this is a slight upgrade of the excellent "Hi-Rez Landscape (Stars)" file uploaded by Phil Demkeston on the Lh'owon Ar'kives (minor smears and hazing were repaired).
You can, of course, use this same DDS file in any version, flavor, or scenario of Aleph One by moving the file to the appropriate folder per A1 flavor.