sidereal
adjective·/saɪˈdɪr.i.əl/
Of the stars, measured by the stars rather than the sun, especially of timekeeping that follows Earth's rotation relative to distant stars. Sidereal feels remote, time taken from the deep background.
In sidereal time the night seemed to have its own clock, indifferent to human schedules and sunrise.
Etymology
From Latin sidereus "starry," from sidus "star, constellation." An older sense of stars as a patterned company, constellations as the units of the sky.
Related Words
stellarof stars; broader and more general
celestialof the heavens; less technical
astralstar-related; often more mystical
eclipticastronomical plane; a different kind of sky-measure