Nouns

(n)celestial sphere, sphere, empyrean, firmament, heavens, vault of heaven, welkinthe apparent surface of the imaginary sphere on which celestial bodies appear to be projected

Adjectives

(a)empyrean, empyrealof or relating to the sky or heavens“the empyrean sphere”
(s)empyreal, empyrean, sublimeinspiring awe“well-meaning ineptitude that rises to empyreal absurdity” (M.S.Dworkin), “empyrean aplomb” (Hamilton Basso), “the sublime beauty of the night”