Finally, a few hours after the RAD was closed, I was able to figure out how to make an SDL Layer Animation. (AgeGlobalAnims are covered in the wiki, but an SDL Layer Animation is not. I don't know if there's support in it with pyprp).
Basically what an SDL Layer animation is, is its a layer animation (similar to all others) that is controlled by a variable in the sdl for the time of day. Similar to AgeGlobalAnim, except that this particular one covers textures. It's found in the sky in gira, which is where I got my idea for. Basically what it is is you take a sky texture with alpha for the day time, then a blend of light blue to dark blue (or whatever color you want the sky to be) this blend will be your alpha blend. Then you take a night time star texture. What an SDL Layer Animation does is use your alpha blend to measure the color of the sky as it goes from day to night, the alpha being used to blend the stars, into the day sky.
There is support for blend animations in Blender, so I'm guessing this is the best place to try and make an SDL Layer animation (But when I attempted to do so it exported it as just a layer animation. no big surprise there)
But, with some hacking with libPlasma I was able to get this:
Eder Licinius at night time, or twilight anyway. I need to retexture the skydome so that the clouds are closer to the ground, during the night time, so you can see more of the stars.