ecliptic
- Key People:
- Hipparchus
- al-Battānī
- Related Topics:
- Sun
- zodiac
- celestial sphere
ecliptic, in astronomy, the great circle that is the apparent path of the Sun among the constellations in the course of a year; from another viewpoint, the projection on the celestial sphere of the orbit of Earth around the Sun. The constellations of the zodiac are arranged along the ecliptic. The ecliptic is inclined at 23.44° to the plane of the celestial equator; this inclination is called the obliquity of the ecliptic. The two points of intersection of the ecliptic and the plane mark the vernal and autumnal equinoxes.
In the ecliptic system of astronomical coordinates, celestial longitude is measured in degrees east from the vernal equinox along the ecliptic. Celestial latitude is measured in degrees north (positive) or south (negative) from the ecliptic to the ecliptic poles. Each ecliptic pole is 23.44° from the corresponding celestial pole.
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Why do we have seasons on Earth?
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What is the zodiac and how does it relate to astronomy?
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How do astronomers use celestial coordinates to map the sky?
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What happens during an equinox?
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How does the Earth's orbit affect what constellations we can see throughout the year?
