Orion the hunter

Orion the hunter
  • the night sky

  • Some of the most interesting stars and deep sky objects are found in this, the most recognisable constellation in the Solar System

Of all the constellations, the most recognisable has to be Orion. The distinct hour glass or butterfly shape contains some of the brightest stars in the night sky and dominates the sky throughout the winter months.

Orion contains some of the most interesting stars and deep sky objects. The bright red coloured star that marks the upper left corner is called Betelgeuse (pronounced either Betelgeeze or Beetlejuice). It is a massive red giant star about 650 light years away. It is so big that if it were placed where our Sun is then its outer edge would be half way between Mars and Jupiter. It has become so large because it is near to the end of its life. Scientists believe that it will explode as a supernova any time now. In fact it may already have exploded and as it is 650 light years away we are just waiting for the light to get here.

The three stars that form a perfect straight line mark Orion's belt across his waist. If you look very carefully just below his belt where his sword would hang, you should be able to notice that the stars in this area have a slight 'fuzzy' appearance. This is the Orion nebula; a huge area of mainly hydrogen gas where new stars are being formed. Even with just binoculars the gas cloud can be easily seen, but photographs taken with the Hubble Space Telescope have shown incredibly complex regions inside the nebula as the gases are condensing together to form stars. It has been calculated that the nebula is over 200 light years across and over 1,400 light years from the Earth.

Orion is such an easy constellation to find that it can be used as a signpost to find other stars and constellations nearby. Follow the three stars in the belt up and to the right and you will come across the bright red coloured star Aldebaran which marks the red eye of Taurus the bull as it bears down onto Orion.

Now follow the three stars in the belt down and to the left this time and you will come across Sirius the brightest star in the night sky. Sirius is a dazzlingly blue/white in colour and outshines all the other stars. Its brightness is down to it being one of the closest stars to the Earth at about eight light years. It is also about twice the size of the Sun but about 25 times more luminous. Sirius is in the constellation of Canis Major (or 'the great dog') and so is often referred to as the 'Dog Star' as it follows obediently behind its master Orion.