Oh and I like what you came up with for the days! We could use those!

As for the stars, moon and any other celestial objects, they are visible everywhere except Varya itself, where the sky is either a stark featureless white or a muddy dark grey.

As for the sun, I've hinted at this in the IC, but it exists as a sort of unknown, nameless entity that society has been conditioned to sort of ignore and endure. It lights up the world, but provides no heat, so it's just kind of part of the landscape. Some also view the sun as having a connection to the Fire Titan, which further adds to the strange custom of ignorance surrounding it.