If you increase the size of each "star view" so that the red background is not necessary they could be more easily scene. So about double the "height" of each constellation.
The problem in photoshop is GIF89 export is built in, I don't have a current version of PS, but PNG was not allowed to export its transparency properties in the version I have. (I don't know about CS versions)
But as a work-around, you could always export to GIF89 format, though only 256 colors allowed.
I like your using stars (as seen from a telescope) with nautical hardware - it kind of reminds me of interstellar navy, although could just as easily be used in a fantasy setting, where sailors have an extraordinary understanding and method of viewing the star.
Nice design idea!