Think these are all the sky-related textuers:
Tx_Sky_Blight.dds
Tx_Sky_Clear.dds
Tx_Sky_Cloudy.dds
Tx_Sky_Foggy.dds
Tx_Sky_Overcast.dds
Tx_Sky_Rainy.dds
Tx_Sky_Stormy.dds
Tx_Sky_Thunder.dds
Tx_Stars.dds
These are constellations and stuff:
Tx_Stars_Mage.dds
Tx_Stars_Nebula.dds
Tx_Stars_Nebula2.dds
Tx_Stars_Nebula3.dds
Tx_Stars_Thief.dds
Tx_Stars_Warrior.dds
I'm really not sure how you'd get the texture names in game without a bit of a laborious process. Bring up console, click on item you want to find the texture for, console window title should give you the object's name. Write that down or use beta comments. Leave game, open up CS and find object in CS. Look in CS to get the model name (.NIF file). Open up model in NIFSkope and that'll tell you what the textures are.