My planets always appear fuzzy and somewhat off :/
Though one thing I did achieve was an exploding star, it was experimental and I think it appeared rather well, but the background stars were noise and didn't work to well.
It had 2 shockwaves, dang they was hard to make XD
But once I get a moment I'll play around with your tutorial more ^^
(I will admit, I never saw the count on the brush settings at the bottom, I always ended up with to many stars per stroke XD)
U'mm, i'll un store some of my space work, I'd appreciate it if you had a gander