Hi folks,
Thanks to raiden I found a tool to make a astronomical cubemap, http://alexcpeterson.com/spacescape . I became familiar with the program and made a skybox from scratch. You are free to use it in accord with the CC license in the zip. The work is grayscale. This decision allows a smaller filesize per amount of contrastive detail. It also allows uniform colorization from within the game and facilitates blending with other cubemaps that would otherwise be disturbed by discordant hues. I would be happy to receive feedback about ways this skybox is used or any constructive suggestions. Cheers