The night sky: Belt of Orion focus for skygazers

The sky at 11 o'clock tonight, looking north

The sky at 11 o'clock tonight, looking north. The summer sky this month features objects such as a red supergiant, a blue giant and three planets (Mars, Saturn and Jupiter).

Encouraged by warm evenings and holidays away from city lights, the summer sky presents a rich selection of interesting objects that are easy to find.

Looking north, the starting landmark is the Belt of Orion (sometimes nicknamed The Pot). This distinctive line of three bright stars straddles the celestial equator and so always rises due east and sets due west. The right hand pair are very luminous stars that formed recently within the gas and dust clouds that fill a good fraction of Orion. This vast stellar nursery lies about 1400 light years away.

Just above the belt is a line of stars known as Orion's Sword. Binoculars will show that the central "star" of the Sword is in fact a gaseous cloud - the Great Orion Nebula.

Below the belt is the orange-coloured star Betelgeuse, which is a red supergiant 430 light years away. This huge bloated star is approaching the end of its life and is considered to be a good candidate to explode as a supernova.

Above the belt is Rigel, a blue giant some 770 light years away.

A line along Orion's Belt to the left (west) points to a red giant star, Aldebaran, in Taurus, which is just 66 light years from us. Aldebaran just happens to lie directly between us and the Hyades star cluster which is 90 light years further away. Aldebaran itself is not part of the Hyades cluster.

Continuing this line further to the left locates the famous Pleiades star cluster (Matariki) which is 370 light years away. With Hyades, this cluster is used by astronomers to help fix the astronomical distance scale. Binoculars will show many more of the fainter stars in both these clusters.

A little further to the left is the planet Mars, looking like a brighter version of Aldebaran. However, as Mars is only 392 light seconds from Earth, Aldebaran is 5 million times further away.

Returning to Orion's Belt and extending a line to the right (east) locates Sirius in Canis Major, the brightest star in the sky. Sirius is one of our closest stellar neighbours at a distance of just 8.6 light years. Straight down the sky from Sirius is Procyon, another close neighbour (11 light years). Continuing this line comes to the two brightest stars of Gemini - Castor and Pollux.

Directly to the right of them (east) is the ringed planet Saturn currently within the inconspicuous constellation of Cancer. Saturn is quite prominent and about the same brightness as Mars.

The other observable planet is Jupiter, which is now very bright in the eastern sky just before dawn.