I actually tried to do a moon up there on the dark side, but it flattened the depth of the scene and the color competes too much with the light coming from the cavern. I think the pure darkness gives it a really deep night feeling.

Nice work 

I think a moon would be okay if it was in the top right corner where you could only see 1/4 of it.

 Nah, I disagree with robin hood, I think a moon would defiantly ruin it.

It's like Jolly Rodger or something.  Very nice :)

A moon would've been nice on the night scene I must say.