Pegasus is a large and prominent constellation in the northern sky, named after the mythical winged horse from Greek mythology. It is one of the original 48 constellations listed by the 2nd-century astronomer Ptolemy and is best seen during the autumn months in the Northern Hemisphere. Here are some key features of the Pegasus constellation:
Great Square of Pegasus
One of the most recognizable asterisms in the sky, the Great Square of Pegasus consists of four stars that form a large square pattern. These stars are Alpheratz (also part of Andromeda), Scheat (Beta Pegasi), Markab (Alpha Pegasi), and Algenib (Gamma Pegasi). Despite being part of Pegasus, Alpheratz is officially listed as belonging to the neighbouring constellation of Andromeda.
M15 (NGC 7078)
Pegasus is home to several deep-sky objects, including the globular cluster Messier 15 (M15). Located about 33,600 light-years away from Earth, M15 is one of the densest and oldest globular clusters known, containing hundreds of thousands of stars.
NGC 7331
Often referred to as the “Deer Lick Group,” NGC 7331 is a spiral galaxy located approximately 50 million light-years away from Earth. It is similar in size and structure to our own Milky Way galaxy and is frequently observed by amateur astronomers.
The Pegasus Dwarf Irregular Galaxy
This is a dwarf irregular galaxy located in the constellation Pegasus. It is one of the closest known galaxies to the Milky Way, located only about 3 million light-years away.
Pegasus is rich in mythology and astronomical wonders, making it a rewarding constellation for both stargazers and astronomers. Its distinctive shape and prominent features make it relatively easy to identify in the night sky.
Visibility
The Pegasus constellation is best observed during the autumn months in the Northern Hemisphere, typically from September to November. During this time, Pegasus rises in the eastern sky in the early evening hours and remains visible throughout the night. It spans a region of the sky from 21 hours to 00 hours in right ascension (longitude) and from +30° to +10° in declination (latitude).
To observe Pegasus, you’ll want to look for it in the southeastern sky after sunset. As the night progresses, Pegasus will move across the sky, reaching its highest point (culmination) around midnight local time.
Autumn is an excellent time to observe Pegasus because it is high in the sky during the evening hours and is well-placed for viewing. However, Pegasus can still be observed in the months before and after autumn, though its position in the sky will vary.
Star Magnitudes
Here are the magnitudes and distances of some prominent stars in the constellation Pegasus:
Enif (Epsilon Pegasi) – Magnitude: 2.39. Enif is the brightest star in Pegasus and marks the nose of the celestial horse. It is a supergiant star located approximately 670 light-years away from Earth.
Scheat (Beta Pegasi) – Magnitude: 2.42. Scheat is a red giant star and one of the corners of the Great Square of Pegasus. It is approximately 196 light-years away from Earth.
Markab (Alpha Pegasi) – Magnitude: 2.48. Markab, part of the Great Square of Pegasus, is a blue-white subgiant star situated about 133 light-years away from Earth.
Algenib (Gamma Pegasi) – Magnitude: 2.83. Algenib is a blue giant star and also part of the Great Square of Pegasus, located approximately 391 light-years away from Earth.
