I really like the natural and realistic feel to this image, you have that rough, detailed style of space art with very a clear sense of putting everything to gether properly. You always have awesome and unique ideas that leave the viewer wondering and amazed. This is just one of your fine examples of a solid piece of space art, which you do so impressivly.
Deffinately always enjoy your planets, they have great quality, and the textures are always interesting and believable, with an atmosphere that isnt boring in any way. The asteroids are very well composed here and they actually look very convincing, great depth and lighting, sometimes hard to fit into scenes without them looking out of place. And although most of the time straight trails of roids look very awkward, you pulled it off exceptionally here.
What I like even more than all that, is deffinately the starfield and nebulae, great depth with the dust, it almost looks exactly like a hubble image, and with a real natural shape. I have never seen textures used so properly for nebulae. The colors are very comforting and easy on the eyes aswell.
I'm not too sure if there could be anything improved here, but if I had to suggest something, it might be to add some multi-colored stars all around the lightsource, just to liven up the image a bit, nothing too crazy, but just a little color to top everything off, I think this would help the "wow" factor of the majority of your pieces, and deffinately with this one. Thats pretty much it, you have a great style, and a great imagination (although this is nothing compared to the crazy ideas you display in your other works.) This is just an all around cool, natural looking spoace scene to enjoy. Keep spitting out the awesome stuff, and we will continue to be impressed!
I really like the nebula, it doesn't steal all the attention and its not too saturated, very subtle. The atmosphere is a little thick, but I can live with that. You still working on that terrain I gave you?