I'm looking for a space sky generator too. Yours even works right in my MacBook. Are you sharing your source?
I hope so it work under Mac

. It is java 1.5 "only".
There is the source. As I said, the code is "a few" dirty.
Basically, I generate all object (stars, planette, gaz) and then I do raycasting for each pixel :
- Stars are spheres
- Gaz are done with a 3D perlin noise.
- Planettes are perpendiculary bitmaps to the view.
For normal sky, I will take a look later. It should not be too mush different from this one. Several suns with bitmap or sphere. Moon with bitmaps. Clouds with a 3D perlin noise (but it need a varation on the final function I think).
By the way, if you have planet bitmap or extra other bitmap (galaxie, black hole,...) that can be add, I will gladly to (there are png file with transparency)