1. Krita
2. Alexb Ate

Krita

Alexb Ate

There a lot of space tutorials out there some are better than others, I have managed to try and select a few of what I think can allow you to get great effects that look like they belong and don’t look completely Photoshopped.I tried to be as varied as possible so there are tutorials for creating planets, stars, nebulas and atmospheric type gasses.