Izar zirkunpolarra, Lurreko latitude jakin batetik ikusita, zeruko poloetako baten hurbiltasunagatik ez da inoiz horizontearen azpian sartzen. Izar zirkunpolarrak, beraz, toki horretatik hurbileneko polorantz begiratuta ikusten dira gau osoan, urteko gau guztietan.

A circumpolar star is a star that, as viewed from a given latitude on Earth, never sets below the horizon due to its apparent proximity to one of the celestial poles. Circumpolar stars are therefore visible from said location toward the nearest pole for the entire night on every night of the year.