The planetary image is pretty low quality. Was that a much smaller image that you scaled up? If you can find or make a higher resolution version of it, that will probably look better.

The edges of the system bands circles are very rough.

To give it just that little bit of extra sci-fi dazzle, try putting a very faint glow on all of the green to give it a phosphorescent look. If you don't have a glow tool, you can just make a copy of all of it, put a blur on it, and reduce the opacity to taste.

You have a typo in the lower-right box: Syestem bands.

Are you using Gimp for this? You might get nicer results from Inkscape, which will give you very clean sharp lines regardless of resolution. I used Illustrator for my own Traveller system maps: Hoffer’s Wake « Bryan Ray, Visual Effects Artist

I'd link to the thread where I posted them here, but search is still off-line.