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.
Perhaps the easiest way to work your way around the winter hexagon is to start with the familiar constellation of Orion and move anticlockwise. The first move is upwards from Rigel to Aldebaran in Taurus. From there, arc over to Capella in Auriga, the charioteer. Continue round the circle by descending to Pollux in Gemini, the twins. The bottom half of the shape is marked by Orion’s hunting dogs: Procyon in Canis Minor, the lesser dog, is the first one, and then continue down to Sirius – the brightest star in the night sky – in Canis Major, the greater dog. From there, head back up to Rigel again.
The chart shows the view from London, looking south at 8pm GMT on 29 January. From the southern hemisphere, the shape is upside down and in the northern sky.
