In this week’s column, I really enjoy bringing to my readers information about two of the more classical constellations mentioned in mythology, Perseus, the Hero, and Pegasus, the Winged Horse.
At this time of year, both of these constellations are in the mid-high eastern sky and as long as there are no autumn clouds to contend with, should be easy to locate. There will, however, be a very bright moon only three days from being full that may interfere.
As I’ve written about several times in other columns, the Horse will be the easiest to locate since it is so large it is difficult to overlook it. The second constellation, the Hero, is also fairly easy to locate but you might find that by using the stars of the “connected” constellation of Andromeda to make it a littler easier.
In mythology, the horse is Pegasus on which Perseus, the hero, rode to rescue the beautiful chained maiden, Andromeda, from being devoured by Cetus the sea monster.
As a sidelight, Andromeda found herself in this predicament because of her mother bad-mounting some celestial goddesses about how beautiful her daughter was when compared to them. The goddesses were insulted by these remarks and condemned Andromeda to death as payment for the slurs.
Facing south, look overhead and slightly to your left for that tremendous square formation of stars. These four stars at the corner of the square represent the body of Pegasus while another line of stars moving generally toward the southwest forms his neck and head.
Pegaus is believed by many astronomers to be the largest of all the constellations although some believe Draco, the Dragon, and Hydra, the Sea Serpent should rank at the top.
There are 4 equally bright stars that form the corners of the Great Square of Pegasus, but the star in the upper left corner is named Alpheratz which is an Arabic name meaning “chained” and actually refers to the “connected” constellation of Andromeda, the Chained Maiden.
As you look at the square, the upper right star is Scheat (SHEE-at), the lower right is named Markab (MAR-kab) and the lower left is Algenib (al-JEE-nib).
The hero of the mythological tale, Perseus, is best found by using the constellation of Andromeda which has its start at the star in the upper left corner of the square.
From Alpheratz, you should see two lines of stars stretching off toward the northeast. This is the constellation of Andromeda and Perseus will be found directly at the end of those two lines of stars.
Perseus is best noted for two spectacular open star clusters identified astronomically by their New Galactic Catalog numbers 869 and 884. They are also referred to as the Double Cluster in Perseus and when viewed through binoculars are beautiful to see.
I’ve found the easiest way to locate these two clusters is to again use the upper line of stars in Andromeda and then continue along an imaginary line a short distance. The first cluster you come to will be NGC 869. The clusters are open clusters so they will not appear as a blob of stars associated with globular clusters.
Perseus is also home to a double star named Algol, often referred to as the “Demon Star”. Algol is a ruddy-looking star to the lower left of NGC 884.
This particular star is one of the best-known eclipsing binaries and over a period of two days, 20 hours and 48 minutes one of the binaries pass in front of the other causing the other star to dim down for about 10 hours and then begin to brighten up again.