Constellations · The Sun · Observing
Ecliptic
Say it: ih-KLIP-tik IPA: /ɪˈklɪptɪk/ noun
Ecliptic: The Sun's apparent annual path against the background stars, or the plane of Earth's orbit underlying that path.
Imagine extending Earth's orbital plane outward until it meets the celestial sphere. That great circle marks the ecliptic, near which the Moon and planets generally appear.
- Example
- The sky chart traced the ecliptic through the zodiac constellations.
- Why astronomers use it
- It provides a reference for solar-system positions and eclipse geometry.
- Tiny cosmic connection
- The Moon's orbit is tilted relative to the ecliptic, so new and full Moons do not always bring eclipses.
Observatory Constellations The Sun Observing
Where to check it
- NASA Science: Universe glossary (opens in a new tab)
- NASA: Basics of Space Flight glossary (opens in a new tab)
- Wikipedia: Ecliptic (opens in a new tab)
Written for Cool Moon Facts in its own words; the sources cover the same idea in more depth.