well, let\'s take the logical approach
we have a giant crystal that reflects/redirects light from the sun on the surface ...this way when the real suns rises on the east, our azure sun sets on the west with a pretty (glittering or rainbowy) effect, because the sun\'s light travels through the crystal
then the crystal\'s light passes towards east, while the real sun\'s passes towards west, and at the sunset we get a similar effect as with the rise (maybe a bit different because the crystal isn\'t symetric and the real sun\'s color may vary while setting or rising)
at night the sun isn\'t there, but the moon and the stars shine ...this produces a dim (probably blue or green) shine from the crystal ...it could be possible that the crystal itself would be seen at night, because at day it\'s too bright.
the stars\' light could also reflect/redirect in the crystal and this light would then (accidentally) point at several smaller crystals in the cealing that would each shine with it\'s own light ...these could \"turn on\" and \"off\" when the light (bacuse of the moving of the real stars and moon) from the crystal would pass them, producing the twinkling :]
why wouldn\'t the \"stars\" shine at day? well, for the same reason why then don\'t on the surface - the sun (_and_ the crystal our case) produces too much light to make them seen
imagine having a coloured, unevenly shaped large lens at the top of your house ...that\'s pretty much what we have here in planeshift :]
p.s. forked from a
different thread