The Night Sky, Explainedby Dmitry Shteynbuk
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Naked-eye astronomyDefinedTerm

Sidereal day

One rotation of Earth relative to the stars: 23 h 56 m 4 s.

Four minutes shorter than the solar day. This is why constellations rise four minutes earlier each night.

Used in these guides

  • Learning the Sky: Five Constellations That Anchor EverythingNaked-eye astronomy
  • Tracking the Sky: Why Equatorial Mounts ExistImaging the sky
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The Night Sky, Explained — by Dmitry Shteynbuk, Miami, Florida

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