Polaris is the bright star positioned directly over the North Pole, the axis around which the Earth rotates. For this reason, the North Star is the only star that does not move from an earthbound perspective. The five circumpolar constellations move around Polaris each night, but each can be identified in reference to Polaris. Because of its constancy, the North Star has been used for centuries by sailors and travelers as a directional guidepost.
The two most commonly recognized of the circumpolar constellations are Ursa Major and Ursa Minor, the Big Bear and Little Bear. Polaris is the star at the tip of the smaller constellation. It is also in a direct line from the outer edge of the larger star grouping. In the United States, these constellations are often called the Big and Little Dippers, since their main stars are grouped in clusters shaped like large ladles or dippers. According to the Challenger Learning Center, these groupings are known as asterisms -- not actual constellations, but recognizable or interesting star patterns within a constellation.
There are three additional constellations revolving around the North Star each night: Cassiopeia, Draco and Cepheus. Cassiopeia looks like a wide, squat letter W; it is also sometimes described as a queen reclining on her throne. Draco and Cepheus are less well-known to most of the general public. Draco is also known as the Dragon, while Cepheus is named after a mythological king.
One of the most recognizable constellations is Orion, the Hunter. This famous warrior appears to be standing and shooting his bow and arrow. He is readily identified by the straight line of three stars at his mid-point, known as Orion's Belt. This constellation is located in the sky over the equator, so it can be seen in both the northern and southern hemispheres. The Southern Cross is a prominent southern hemisphere constellation, featured on the flags of Australia and New Zealand, among others.