circumpolar stars

circumpolar stars

(ser-kŭm-poh -ler) Stars that are permanently above the horizon from a given observational point on Earth, i.e. they never set. For stars to be circumpolar from a given geographical latitude ⊂, their declination (angular distance north or south of the celestial equator) must be greater than 90° – ⊂. For an observer at the north pole all stars in the northern hemisphere of the celestial sphere will be circumpolar whereas at the equator there are no circumpolar stars although almost all stars will be seen at some time during the year. For an observer at the south pole, all southern hemisphere stars will be circumpolar.