Not nad but you overdid it a bit with the stars ^^ They seem unnatural as well, there seems to be too much order in their placement. And maybe try adding a planet or something?
Everything looks good on the version with the planets, but like they said, blend them in. It would most likely be better if it looked natural.
its getting better like everyone keeps saying blend the planets a bit more especially that ringed one, aybe a bad cut job on it or something but it needs to definetly be blended and I agree with Neuron 100% do not use lens flares brush in your own lighting it will add so much more to the piece. also you need to take away alot of stars.... WAY too many.
Unfortunately...I don't have ANY lens flares...I used a brush (color dodge and different sizes...) btw I gave it a more "windy" or "worn" blend look.
Looks pretty average compared to the other work I've seen here tbh. You seem to get the general idea but not that much of an eye for how it could / should look. Delete the planets completely, replace them with high quality images, those are poor. Blend them. The reset is alright.
The brown planet just doesn't fit, the colours are just, random and make no sense corresponding with the surroundings. Same with the big planet, you've got a huge red star yet there's absouletely no red on the blue planet, which isn't making much sense. The big starts are far too big. It is getting better mind. Like said before, read some planet tutorials and remake them, seems for the big one you've used a duplicated texture.