Sidereal time

Pronunciation: /ˈsaɪdˈɹiɫ ˈtaɪm/

Sidereal time (noun)

  1. A way of measuring time by how far Earth has rotated compared with distant stars.
  2. Time used to help astronomers aim instruments at objects, based on Earth’s rotation relative to stars.

Examples

  • Sidereal time helps track the sky using stars instead of the Sun.
  • When sidereal time changes, the stars appear to shift across the sky.