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sidereal - adj., of or relating to the stars or constellations; (of divisions of time) determined by daily motion of the stars.
A sidereal day is the length of time it takes for a star to return to the same position in the sky, which because of the motion of the earth around the sun is a little less than 4 minutes shorter than the time it takes for the sun to do the same. Wikipedia has a good diagram explaining. From French, from Latin sidereus, adjectival form of sidus, star, constellation, possibly from PIE root *sweid-, to shine.
More astronomic circles.
---L.
A sidereal day is the length of time it takes for a star to return to the same position in the sky, which because of the motion of the earth around the sun is a little less than 4 minutes shorter than the time it takes for the sun to do the same. Wikipedia has a good diagram explaining. From French, from Latin sidereus, adjectival form of sidus, star, constellation, possibly from PIE root *sweid-, to shine.
More astronomic circles.
---L.
