This is so amazing! I have a question about your work, how do you do extremely close up planets? Like the one in the foreground? Whenever I try it the texture gets blurry, how are yours so sharp and crisp? This is truly beautiful!
There's really no flow in the picture (left side crowded with elements, right side rather empty). Though the nebula helps somewhat in creating a dynamic flow for your eyes, its not enough combined with other compositional flaws though. Where there are lines and compositions to draw your eyes over the image, they're too straight and uninteresting (the straight line from top to bottom on the left side: Galaxy -> moon/planet -> close up -> moon planet for instance). It's also a bit hard to distinguish what it is that's supposed to be the central object here; the beautiful galaxy (should be, imo ) and the bright shining star both competes (another two objects too straightly aligned towards each other) against each other for the attention.
All in all it looks a bit square - everything in lines and around the edges of the picture.
It's still a beautiful piece though. I think it deserves a bit better though...