Nirn has two moons, Masser and Secunda. The other astral bodies in the sky above Nirn. It would be great to look up at the sky in Tamriel is see the actual moons.
To make it even better... seeing the various constellations according to the Lore. The constellations can move above the sky in real time and depending on mundus stone a player has, they would get a bonus based on the season of the constellation.
The Serpent travels across the entire sky separate from the other constellations and can either be a curse or blessing. Anyone that has the Serpent would be blessed, but if the Serpent is in the same season as any of the other Constellations, the player with the other would be cursed.