The corona does seem a little overbright but I like the banded starfield and the way you used just a few extra colors in the planets surface. I do like the way the reflected light hits the moon.
A lens flare wouldn't go astray, and the light noise around the clusters (which incidently are parallel) seems a little simple and its shape not quite relative to that of the clusters.
I look forward to the rework!
It seems to me that what wears us down the most in life aren't the chances we take, but the chances we dont take, the dreams we put aside, the adventures we push away, the questions that are never answered
Nice work. As you say it could use a little fine tuning but nothing too drastic. I think the main change I would recommend is to soften the contrast of the bright light around the planet (ie remove the "halo" effect).
Nice..I think this would do well with some clouds and more frequent stars (noise)...there are tutorials on it. I guess it's a style preference for me, but this is still good.