Actually, I did want the tree as a silohette but everytime I would get it to where the moon was actually a crescent, it would black out everything else completely, you couldn't even see the tree. But if I exposed the tree correctly, the moon would over expose and show the entire moon, only the crescent would be blown out. Does that make sense?
If not, I can post pictures of what was happening. This was my first attempt at ever trying it, so I was changing the settings alot.