Circumpolar star

A circumpolar star circles the celestial pole without setting below the horizon for a given location. Whether a star is circumpolar depends on the observer’s latitude and the star’s declination.

Celestial pole: The point in the sky where Earth’s rotational axis, extended outward, appears to meet the celestial sphere. Circumpolar stars trace circles centered on the celestial pole.
Polaris: The current northern pole star, located close to the north celestial pole. Its near-polar position makes it circumpolar throughout much of the Northern Hemisphere.
Rising and setting star: A star whose apparent daily path crosses the horizon, causing it to rise and set. Unlike a circumpolar star, it passes below the horizon during each daily cycle.
Earth's rotation: Earth’s spinning motion around its axis, completed approximately once every day. It produces the apparent daily circles traced by stars around the celestial pole.
Declination: An angular coordinate measuring a celestial object’s distance north or south of the celestial equator. A star’s declination combines with the observer’s latitude to determine whether it sets.
Ursa Minor: A northern constellation containing Polaris and the Little Dipper asterism. Its stars provide familiar examples of objects that circle the north celestial pole.
Never-rising star: A star that remains below the horizon throughout the daily cycle for a given location. It is the opposite visibility case: the star never appears above the horizon.
Axial tilt: The angle between a rotating body's spin axis and the perpendicular to its orbital plane. Earth’s tilt establishes the celestial equator’s orientation relative to the horizon.
Latitude: A geographic coordinate measuring angular distance north or south of Earth’s equator. The observer’s latitude sets the altitude of the celestial pole and changes which stars remain visible.
Ursa Major: A northern constellation containing the Big Dipper asterism. Its prominent stars can be circumpolar at northern latitudes and help locate Polaris.

Linked from 12 pages