FOR thousands of years people around the world have looked into the night sky and made patterns out of the stars. Each civilisation had their own set of pictures they generally agreed upon and were usually completely different to those of any other civilisation.
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In 1922 however, the International Astronomical Union decided that there should be only 88 official pictures recognised internationally. These official pictures, or constellations, are based on a list made almost 2000 years ago by the Greek astronomer Ptolemy.
Being made so long ago however means that the pictures tend to be unfamiliar to our everyday lives. Trying to make out the exact picture of a constellation is also usually very difficult.
A lot of people consequently make up their own pictures from the stars, ones that are relevant to today and easier to find night after night. Since these personal pictures are not part of the official constellation list they are known as asterisms.
There are a few easily visible and well known asterisms. Perhaps the most well known one is visible in the northeast of an evening at the moment, the Saucepan. The stars that make up the saucepan shape are however meant to represent the belt and sword of Orion, the hunter.
Now, apart from being made up of some of the brightest stars, the Saucepan contains some fascinating objects.
Within the handle of the Saucepan lies one of the best, brightest and most easily seen nebulae, the Orion Nebula. Within this huge cloud of gas and dust visible to the unaided eye, stars are currently being made.
Between the handle and the base is a star that turns out to be made up of five members all in an intricate gravitational dance.
Near one of the stars making up the base of the saucepan is the famous Horsehead Nebula.
But perhaps most interesting is the middle star of the base. Known as Alnilam, it is the heaviest star we can see with the unaided eye.
Alnilam is not a binary star so measuring its mass is difficult, but by comparing it with other stars we can estimate that it weighs an amazing 80,000 trillion trillion tonnes, some 40 times more than the sun.
It is also hundreds of thousands of times more luminous than the sun, but fortunately lies about 1300 light years away. This is much more distant than almost every other star visible with just our eyes so instead of being overwhelmed by Alnilam's brightness we see it merely as the 30th brightest star in the sky.
So while you’re outside tonight, or in fact any clear summer night in the coming months, why not take the time to explore The Saucepan.
