Constellation for December 2022 – Perseus
Perseus was a great hero in Greek mythology who saved Andromeda from the sea monster Cetus, who is now swimming in the night sky beneath Perseus and Andromeda. To find Perseus, which looks like a man climbing up a rock face, we need to go back to the four stars in a line mentioned in the section about Andromeda and Pegasus. If we follow the line from Scheat, Alpheratz, Mirach, and Almach, and continue in the same direction we reach the bright star Mirfak in Perseus. It can be recognized by the many small stars around it.
If we then go up two stars and reach Miram, we can find the Double Cluster [1] – two prominent star clusters in the sky together – between Miram and Ruchbah in the W-shaped constellation of Cassiopeia. The Double Cluster is so large that it is best seen in binoculars. In a dark area (such as Norfolk) it can be seen with the naked eye, appearing like two owl eyes.
The two clusters are both very young, only 14 million years old, and are both about 7,500 light years distant. Now go below Mirfak to a bright star slightly to the right (or west). This is Algol, which dims for ten hours every three days because a dimmer star passes in front of the main star. Between Algol and Almach you can spot another star cluster Messier 34 [2] using a telescope. It is 1,500 light years away from us and is about 250 million years old.
Finally, just below Atik there is a 6.8 magnitude star X Persei, which is a remarkable X-ray-emitting binary system with a large star losing mass to the neutron star it orbits.