Well I just started using photoshop, and this is the second thing that Ive made, and I would just like to hear some of what others think about it. I know that the white on the planet looks a little rough and obvious, but it IS my 2nd thing I made, and I didnt know what to fill the remainder of the area with, so...
give it some difference in size and shape of the stars, the green color looks...horrible and ugly...the lighting on the planets is off, and uh...usually I would have a good comment but all I can is say you have a ok start.
If this green is like a gas or cloud, then it needs some depth. At the moment you have 2 planets in the forground, with the gas behind that and another planet behind that. The gas should be partly infront of the planets, and getting denser in some regions to provide a bit of variation. Also i feel that the green is a bit too strong, and there should be a much greater colour variation.
yeah give a variety with the size of the stars also maybe lower the opacity on the green parts. also if you want it to look more like clouds select random parts and feather them just make the kinda small and not around a huge region