I sugguest having more light, and then add a moon and colorize to a nighttime shade of blue in Photoshop. Teragen does not do moons well at all, since its actually the sun :?
The second one is the first version, the blue one is the updated version. Thanks for the comments Jepp, I'll go work on it some more later to fix it up.
I had this as the first version but was told more contrast would look better, which resulted in more black. http://img39.exs.cx/img39/9210/shattered1.jpg