Pegasus the Winged Horse Constellation


Welcome to Learn the Sky, your online
resource for learning about the stars. Learn the Sky is now on Patreon, so if
you would like to support this channel in order to learn more about the sky,
please visit our Patreon account, the link is listed below.
We are also offering new online courses, so if you’re interested in learning
about the sky in greater detail and would like a guide to help you walk
through the sky, please visit and check out our online courses.
Welcome! My name is Janine and in this video we will explore the constellation
known as Pegasus. First let’s look at some of the mythologies that surround
this constellation. In Greek mythology, Pegasus is a winged horse who is the son
of the mortal Medusa and Poseidon when Perseus beheaded Medusa, Pegasus and his brother emerged from her neck. Once born he was taken in by the muses of Mount
Olympus and raised there. One story of Pegasus traces back to the Greek hero
named Bellerophon. He captured Pegasus and rode him in his fight with the
Chimera. It was said that Bellerophon attempted to fly with Pegasus to join
the gods, but fell back to earth. Pegasus, however, made the journey, then becoming a constellation and the servant of Zeus. There are multiple myths and legends
about Pegasus and they vary from culture to culture just like many of the
constellation stories. Now let’s identify the distinctive pattern of Pegasus. The most obvious feature of Pegasus is the Great Square which is outlined here this
shape dominates the sky in the autumn and it takes up a fairly large portion
of the sky. This shape is also identified as the asterism called the Great Square
of Pegasus. Remember an asterism is not a true constellation but rather an
easy-to-find shape within larger constellations. They can be used as
markers to help us find our way around the sky. So here is a portion of the
constellation Pegasus and it represents a winged horse and is classified as a
seasonal constellation. Now Pegasus is a difficult
constellation to get in a photograph because it is so large, but here you can
see the Great Square of Pegasus and then the head comes off this way and two of
the legs this way. Here is a picture of Pegasus that I took with my camera phone
and while the quality of it isn’t that great it’s a good photo because it does
show the entire constellation of Pegasus. So before I point it out for you, are you
able to identify the Great Square asterism that’s right in the center of
the photo? If you can, then you should be able to find the rest of the
constellation so here it is we’ve got the great square right in the center and
then the head that jets off right here and the two legs right here. Now Pegasus
does share a star with the constellation Andromeda, so you can start to see that
constellation come off the Great Square as well. Now that we know the pattern of
Pegasus let’s take a look at the bright stars that sit within its boundaries. So
as we take a look at the official star map of Pegasus, you hopefully can
identify the Great Square, the two legs and then the head. The brightest stars
are seated within the Great Square, so let’s take a look and zoom in there. The
Alpha star is known as Markab, and it’s an Arabic name that means ‘saddle of
the horse.’ Alpha Pegasi is a B type giant star which means that its core has run
out of hydrogen and it’s beginning to evolve beyond the main sequence phase of a star. It’s in the southwest corner of the Great Square and is estimated to be
133 light-years from Earth. So here is a picture of the Great Square and
hopefully you can see it right in the center. This is where Markab is.
Beta Pegasi also names Scheat, is a red giant star and the second brightest
star in the constellation of Pegasus. It’s name is Arabic for ‘upper arm’ and it
forms the upper right corner of the Great Square. It’s luminosity is 1500
times that of our own Sun. Algenib is the gamma star of this
constellation. Its name is Arabic for the flank and it is a large star with almost
nine times the mass of the Sun and close to five times the sun’s radius. This star
has also run out of hydrogen and is starting to evolve out of the main
sequence phase. Now let’s examine the celestial objects that sit within the boundaries of Pegasus. There’s a galaxy, a globular cluster and a cosmic mirage known as Einstein’s Cross. First let’s take a look at NGC 7331. It is a
cluster of galaxies, but the main one is this large spiral galaxy to the right of
the image and it’s often referred to as Milky Way’s twin because it’s very
similar in structure. There are a few other satellite galaxies that surround
this larger galaxy and if we zoom in here you can see it’s an unbarred spiral
galaxy and it’s estimated to be 40 million light years away. Messier 15 is a globular cluster that
sits within the boundaries of Pegasus. It is estimated to be thirty three thousand
six hundred light years away and it is one of the most densely packed globular
clusters known in the Milky Way galaxy. It is also one of the oldest; it has an
estimated age of twelve to thirteen billion years old and it contains over
100 thousand stars. Huchra’s Lens is the name of the lensing
galaxy that’s in front of the Einstein Cross. The galaxy is named for astronomer John Huchra. Here you can see that the lensed quasar resembles a cross. So the
gravitational force from the galaxy creates four images of the quasar behind
it. Amateur astronomers would be able to see some of the cross using telescopes
but it would require extremely dark skies and telescope mirrors with
diameters of eighteen inches or more. Let’s review what we’ve learned about
Pegasus the winged horse constellation. It is best seen in the autumn months and
it’s classified as a seasonal constellation. The best way to find it is
to look for the asterism known as the Great Square of Pegasus which takes up a really large portion of the sky. In terms of celestial objects that contains a few
galaxies, a globular cluster known as Messier 15 and a cosmic mirage known as Einstein’s Cross. I wish you luck finding this constellation and if you have any
questions or comments be sure to leave them in the spot below. I also want to
send a huge thank you to David Cocklin for allowing me to use his amazing
photographs for my videos. Be sure to check him out on Twitter. Good luck
finding Pegasus!


6 Responses

  1. Daniel Battle

    November 20, 2019 5:35 am

    Man I love astrology! I can see the Pegasus constellation from my backyard. Saint Seiya brought me over to your channel. Lol 😆 😆 Thanks for the informative channel.

  2. ExultantRaichuFan123 And Stuff!

    December 23, 2019 12:11 pm

    Okay I’m late but, pegasus is my FAVORITE constellation. My top 3 is Pegasus, Aquila, and Libra


Leave a Reply