KEY POINTS:
The dominant constellation of our night sky over summer is Orion, the Hunter. It is easy to find above the eastern horizon after sunset and is standing upright in the northern sky by 10pm.
Orion straddles the celestial equator so it is seen from both northern and southern hemispheres. It is useful because it provides some key landmarks for locating numerous stars, clusters and nebulae.
The best place to start is Orion's Belt which is formed by three bright stars in a line. The Belt is part of a pattern of stars commonly called the Pot in New Zealand. The bright star above the Belt is the blue supergiant, Rigel. The bright star below the Belt is the red giant, Betelgeuse. Both these stars dwarf our Sun.
Continue the line of the Belt to the left and you will come to another red giant star, Aldebaran, the brightest star in Taurus (the Eye of the Bull). Aldebaran lies about 65 light years from us but the group of stars surrounding it is a star cluster called the Hyades, a further 90 light years away.
Continuing this imaginary line about the same distance to the left again you will find the Pleiades (Matariki). This beautiful young star cluster is about 370 light years away and is important in astronomy for determining the distances of stars. Most people can pick out seven stars with the unaided eye and for this reason it has been known as the Seven Sisters since antiquity. With binoculars you can see many more cluster members.
Returning to Orion's Belt and extending its line to the right, you will find the brightest star in the sky, Sirius, which is one of our close neighbours at just 8.6 light years. Sirius is in Canis Major (the Big Dog) and is commonly called the Dog Star.
A fainter line of three stars above the Belt forms Orion's Sword (the handle of the Pot). Binoculars will show that the middle "star" is fuzzy while even a modest telescope reveals the details of this giant gaseous stellar nursery and the hot young stars imbedded within it. This is the closest star-forming region to us yet it is 1500 light years away.
We are moving into the best viewing times for Saturn. It currently rises at 11pm in Leo and easily outshines the star Regulus. By midnight Saturn and Regulus make a striking pair in the north-eastern sky.
Jupiter is in Scorpius and is very bright in the eastern sky before dawn. Next to it is the star Antares and below it the planet Mars.
* Grant Christie is an astronomy researcher who writes a monthly column for the Herald.
