Starwatch: the brightness of the Winter Hexagon

Six stars from separate constellations form a prominent asterism' in the cold January skies

Not all star patterns are called constellations. Strictly speaking, constellations are the areas of the sky that contain familiar patterns - such as Taurus, the bull, or Orion, the hunter.

The patterns themselves are called asterisms but not all asterisms are related to constellations. In the northern hemisphere winter, a particularly prominent asterism is known as the Winter Hexagon or Winter Circle. It contains bright stars from six separate constellations, marked on the chart in yellow.