Northern Circumpolar Constellations
Constellations come,
and climb the heavens, and go,
And thou dost see them rise,
Star of the Pole!
and thou dost see them set,
Alone, in thy cold skies,
Thou keep'st thy old unmoving station yet.
What does circumpolar mean?
Circumpolar means to circle around the pole. Circumpolar stars or constellations daily trace circles around the north celestial pole, without setting or dipping below the horizon. They move in a counterclockwise direction. On any given night, the constellation is visible during a portion of the circle; the rest is traced out when the constellation is hidden in the daylight sky.
Important circumpolar constellations:
Ursa Major, the Big Bear (includes the Big Dipper)
Ursa Minor, the Little Bear
Cassiopeia, the Queen of Ethiopia
Cepheus, the King of Ethiopia
Draco the Dragon
In Summary
As we face north from Norman, Oklahoma, the north celestial pole is found 35 degrees above the northern horizon (latitude of Norman = 35 degrees north).
Polaris, the tip of the tail of Ursa Minor, the Little Bear, marks the north celestial pole to with an error of about one angular degree.
The pointer stars of the Big Dipper point toward Polaris. The pointer closest to Polaris is Dubhe, the tail of the Big Bear, which lies about 28 angular degrees from Polaris.
Every 24 hours the Big Dipper completes a full circle around Polaris (or the Big Bear circles the smaller bear). This counterclockwise motion can be used as a star clock to tell local, universal, or sidereal time.
The Big Dipper is found crossing the meridian at midnight near the end of March.
As explained in Starstruck Tonight:
Ursa Major or the Big Bear is the third largest of the 88 constellations. Seven stars form a familiar group of stars, or an asterism within the constellation. In America they are called the Big Dipper or "Drinking Gourd," and in Britain the "Plough" or the "Wain." The Big Dipper is one of the most easily recognizable groups of stars in the sky. It is referred to as circumpolar because it never completely sets below the horizon, but is visible in northern skies year-round.
You can learn, as did ancient sailors and western cowhands on the night watch, to tell the time of the night by the position of the Big Dipper. Due to the daily rotation of the earth, the dipper rotates around the north star every twenty four hours.
As the night hours pass and the Earth turns on its axis, the stars turn in circles around Polaris, which appears to stand still. Some constellations are close enough to Polaris that they never set below the horizon. These are the circumpolar stars. Most stars are farther away from Polaris, and fall below the horizon. These appear to rise in the east, cross overhead, and set in the west, much like the Sun.