Since the moon is the main light source and the scene is all about the two characters, I would emphasize this and give them some pale rim light to make them more important.
If you think it’s ok, then it’s ok. The light intensity depends on the mood you want to convey. I assume that if you like it, your intention is coming through. Do take a look at the shadows, though. As mobimo points out, the main light source is the moon, but the smaller figure seems to be standing in the shadow of a tree.
As to Skydomes, the only cure is to find one with a larger resolution. Check NASA websites, the Hubble telescope has taken some pretty amazing ‘night’ skys.
I agree with the rim light idea. A rim light is basically a light behind the actors that is facing the camera. For the most part it is used to separate the actors from the background. Google it for more info, but I agree with Mobimo that it would probably be a good addition to the scene.