What you need
Clear night skies
Advertisement
Binoculars (optional)
A telescope (optional)
Journey to the stars
BETWEEN December and March, there is something special for stargazers in most of the world to watch out for. You will be able to see a pattern of stars, or asterism, made up of six bright stars. It is called the Winter Hexagon or Winter Circle in the northern hemisphere, or the Summer Hexagon or Summer Circle in the southern hemisphere.
Each of these stars is the brightest in their constellation. The asterism can be seen from anywhere except the most southern parts of New Zealand, Chile and Argentina and further south. Depending on where you are in the world, its orientation with the horizon will change, but the pattern of the stars with respect to each other will stay the same.
In previous columns, I have revealed how to find Orion and its brightest star, Rigel. Rigel makes one corner of the hexagon. You can find the hexagon’s next two stars by extending Orion’s belt. In one direction, you will find Sirius, the brightest star in the night sky. It will be low in the horizon in the northern hemisphere and higher in the southern hemisphere. Go in the other direction, and you will get to a bright star in Taurus called Aldebaran, the next point.
To find the other stars in the asterism, start by looking for Pollux, in the constellation Gemini. Draw a line from Rigel, through Orion’s Belt and keep going, past the red bright star Betelgeuse and on until you see two bright stars close together. These are Castor and Pollux, the twin stars in Gemini. The brightest of these, Pollux, is another point on the hexagon.
It should be easy to fill in the gaps where the remaining two corners of the hexagon lie. If you look between Sirius and Pollux you will see a bright star, called Procyon, in the constellation Canis Minor. Follow the lines of the hexagon round to look for a star shining brightly opposite where Sirius sits. This is the final star in the hexagon, Capella, in the constellation of Auriga.
In the southern hemisphere, you can extend this asterism to include another star, called Canopus. This star is in the constellation Carina. It is the second brightest star in the night sky after Sirius, and you can find it by drawing a line from Canopus to Sirius then continuing it until you see a bright star.
Now we have them all: starting from Rigel and going clockwise, the hexagon’s stars are Sirius, Procyon, Pollux, Capella and Aldebaran. There are different ways to remember their names, but I think of it as the RSPPCA, the Royal Society for the Protection of People who Care about Asterisms. If you find the two stars beginning with P hard to recall, remember Procyon is in Canis Minor and Sirius is in Canis Major, and the two dog constellations are loyally next to each other.
Abigail Beall is accompanying a 91av Discovery Tour to Chile, the world capital of astronomy in November 2021.
Abigail is also the author of The Art Of Urban Astronomy (Buy from *)
Stargazing at home appears every four weeks
Next week
Science of cooking
These articles are posted each week at
*When you buy through links on this page we may earn a small commission, but this plays no role in what we review or our opinion of it.
