A big practice test before I paint Jupiter for a teacher I owe something to.
I took a canvas and painted it black, let it dry then used black and white gesso to paint in some general shapes.
Painting planets is very simple and easy to do, if you can paint a circle you can paint a planet.
like how the planets came out. Not so much on the 'cloud' nebula or the comet tail but overall I am happy with my test results.