PEGASUS The "Winged Horse" pronounced PEG-uh-suss.
This constellation is the winged horse of Greek mythology, born from the blood of Medusa after she was slain by Perseus, who lies nearby in the sky.
Ptolemy assigned 20 stars to this ancient northern constellation. The most famous feature of Pegasus is the "Great Square", outlined by four bright stars, one of which is now assigned to Andromeda, although astronomers of old new it as δ Pegasi. The constellation appears as an upside-down horse to northern hemisphere viewers, but appears right-way up to us.
To find Pegasus, look north, about halfway up the sky, and find the great square of bright stars.
Some stars and interesting objects in the Constellation.
α Pegasi (Markab, the saddle) is a magnitude 2.5 blue-white star 100 light years away.
β Peg (Scheat, the shoulder) is a red giant star ninety times the Sun's diameter. It varies in magnitude 2.4 to 2.8 about every month.
γ Peg (Algenib, the wing or side) is a magnitude blue-white star 490 light years away. It is a β(beta) Cephei type variable star, but its light variations every 3 hours 40 minutes, are too small to be noticed to the unaided eye.
ε Peg (Enif, the nose), is a magnitude 2.4 yellow supergiant 520 light years away. Good binoculars and small telescopes reveal a wide bluish magnitude 8.7 companion star. Larger telescopes also show an 11th magnitude companion closer to the primary star, making this a triple star system.
ζ Peg (Homam), is a white star of magnitude 3.4, 160 light years away.
η Peg (Matar) is a magnitude 2.9 yellow giant star 170 light years away.
π Peg is a very wide double star, with white (magnitude 4.3)and yellow (magnitude 5.6) components visible in binoculars. The stars are about 310 and 320 light years away, respectively.
α And (Alpheratz or Sirrah) (δ Peg of old), is a magnitude 2.1 blue-white star 105 light years away.
M 15 (NGC 7078) is a beautiful outstanding, bright globular cluster about 40,000 light years away, in a field well sown with stars. While it at the limits of unaided eye visibility, it is easily seen in binoculars or small telescopes, with a nearby 6th magnitude star acting as a guide to its location. It rises to a bright central peak with scattered faint outliers in irregular rays. A small planetary nebula is projected on this cluster, but an OIII filter and a good aperture is needed to see it.
NGC 7331 is a 10th magnitude spiral galaxy with a dark lane along its central region visible in photographs.
Pegasus is to the north at about 10 pm (NZDT) from mid October to mid November. The two upper stars, α Peg and γ Peg have an altitude of just over 30° from central New Zealand, a littler higher in the north of the North Island and a little lower in the south of the South Island. The lower two stars have an altitude about 20° from central NZ.
By the end of November the square will be getting rather low to the north-west once the sky has darkened.