Airbrush Practice

So, we've started working with airbrushes for some reason or another.  I really see no point in learning to use them, unless one of the projects is retouching a large-scale image; which i hardly doubt.   So for today, we had to paint a planet; with a space-like background on it of course!  So i did this little number, the planet is okay, just okay.  I like the background better actually.  I think scale could have helped here.  I think i was more free to work with the airbrush on the back because i was not working in such a confined space.  I will have to keep that in mind.  Well here it is, I also added a few variations on it as well, because they just seemed to fit in well, enjoy:

The one on the farthest right was my first attempt at the airbrush, it did not work out as planned because my aribrush needed some serious cleaning!  We've only just started working with them and already it's filthy!  Either did a really bad job cleaning it to begin with or someone just left gunk in it!  I think it's the later one, i mean when i pulled the cap off, purple ink fell on my hand!  Who does that!  I looked to see who had used purple the next day.  The other blue one was my first shot at a planet.  I think it's just okay.  I think scale would rally help as well as making it look a little less flat.  the orange ones are just practice again.  

The way I see it, airbrushing can only go up from here.