I could swear they changed positions in the Vanilla sky. Perhaps I was merely mistaken.
They did? Well, I hope you're not mistaken, because that would have been really cool.
Anyways, starwarsguy, the constellations move around according to lore, I think based on the serpent and which lesser sign he is attacking in that month or something like that. You should go to the TES lore area and ask what they think happens with that. If you wanted to implement such a thing you could simply create a separate texture and mesh for each separate sky you would need to accommodate the lore and then just disable and enable them according to what month it was.
Edit: I missed the part where you were referred to the Firmament and said it was a cool book. I suppose my implementation for a future upgrade to your skies still works though.