Constellations · Observing
Circumpolar
Say it: sur-kum-POH-ler IPA: /ˌsɜrkəmˈpoʊlər/ adjective
Circumpolar: Describing an object that stays above the horizon throughout its daily circuit for a particular observer.
As Earth turns, stars appear to circle a celestial pole. Some circles never cross the local horizon, making those stars circumpolar from that observing latitude.
- Example
- From her northern observing site, the star was circumpolar.
- Why astronomers use it
- It helps observers know which stars remain geometrically above the horizon throughout the night and year.
- Tiny cosmic connection
- Above the horizon does not mean visible in daylight, through clouds, or behind a mountain.
Observatory Constellations Observing
Where to check it
Written for Cool Moon Facts in its own words; the sources cover the same idea in more depth.