Seeing Stars: The two bears
Look to the north this month and you will find two bears dominating our night sky.
The constellation of Ursa Major, “The Great Bear”, contains the easily recognisable pattern of stars we call “The Plough” which makes up the back half of the bear’s torso and its tail.
Most skywatchers will have seen “The Plough”, but have you ever spent some time taking in the entire shape of the Great Bear?
As always, you will need a dark sky spot and no moon present to see the full constellation as some of its stars are faint.
Unlike some animal representations in the constellations, Ursa Major does in fact resemble a bear.
Use the diagram accompanying this column to make out the fainter legs and head of the bear in the night sky.
This constellation was first described as a “great bear” by the ancient Greek astronomer Ptolemy.
However, these same stars have been described and used for storytelling or navigation by many other cultures. The ancient Egyptians described the stars as an ox and handler and Native American people saw the same stars as wolves, bison, elk or caribou.
The other bear in our night sky, Ursa Minor, “The Little Bear”, is close by.
This constellation is not as recognisable as Ursa Major but you can use the two pointer stars to get to it.
The pointer stars are the last two stars in the bowl of The Plough. Draw a line through them upwards until you hit the next bright star.
This is Polaris, the North Star, which is the tip of The Little Bear’s tail.
Polaris is the brightest star in Ursa Minor and stays fixed all night long.
Earth’s north pole points almost directly at this star so when Earth spins on its axis, it appears that all the other stars in the sky pivot around Polaris.
In the past, travellers heading north simply aimed themselves in the direction of Polaris.
Travellers heading west kept the star to their right side – the starboard side on a boat.
In mythology, there are lots of stories relating to the two bears.
One is the story about the woman Callisto, who is turned into a bear by one of the gods.
When her son Arcas meets her in a forest and is about to shoot her (as a bear), the god Zeus turns him into a bear also and then places them close together in our night sky for us all to see.