Nasa photos. Look for the blue marble, massive textures at close to 4 gigapixels. Photos of clouds (available at Nasa) are also useful. I plan to make textures myself, from photos I have taken (as I now have a very good camera). I have applied textures that I have created in Apophysis as well, although not in my recent pictures here.
I love all the amazing little details, but those blue glows around the planets are distracting IMO and I agree with AC117 i think it needs more empty space, but those aren't deal-breakers - it's still very high quality work
A beautiful representation of the celestial bodies that flow through space. The detail upon the planet looks outstanding and the nebulaeic remnants as they fade in and out of the solar light look beautiful.
The only thing that puts me off are the triangular lens flare effects near the star. I'm not sure if they were intentional, but to me it just feels out of place and sort of tinges the atmosphere of the piece. Other than that, the piece is lovely.