November 20, 2021: The great winged horse Pegasus flies across the southern sky during the early evening.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 6:47 a.m. CST; Sunset, 4:26 p.m. CST. Check local sources for sunrise and sunset times for your location.
Pegasus, the Great Winged Horse, flies westward in the southern sky after sunset. Step outside about two hours after sundown. Pegasus is high in the southern sky.
A large box of stars, equal to stars’ brightness in the Big Dipper, is high in the south, about two-thirds of the way up in the sky.
A star, Alpheratz, is borrowed from Andromeda to make the shape. At one time the star – meaning “the horse’s navel” – was shared between the two constellations. On today’s star maps it belongs to Andromeda, so we use it to construct “The Great Square of Pegasus.” From the northern hemisphere, the horse appears upside down.
Two other stars in the Great Square are Scheat – “the leg”- and Algenib – “the side.”
The neck begins at Markab – meaning “Anything on which one is carried.” (That anything could be a horse, camel, or ship.) Leaving that star, look to the southwest (lower right) for two stars that are on the horse’s and continue to Baham, which means “the lucky star or the flock of lambs, kids, and camels’ colts.” This star mark’s the eye.
From Baham, look northwest (to the upper right) for Enif, “the horse’s nose.”
With a binocular continue northwest to the star cluster Messier 15 (M15 on the chart). The star and the cluster easily fit into a binocular’s field of view. It appears as a fuzzy star in the field. Through a telescope some stars can be seen, but them seem to mash together at the center, although they are far apart.
Messier 15 is known as a globular cluster. Globulars have chemistries and orbital paths around the galaxy that are different from the sun and its stellar companions in the plane of the Milky Way galaxy.
By mapping the positions of these clusters about a century ago, astronomers were able to find the shape of the galaxy and the sun’s place in it. Initial estimates of the ages of the clusters were around 3 billion years. This astonished astronomers that began detailed studies that continue today to find the age of the universe.
During late November and early December, look for Pegasus high in the southern sky during the early evening hours.
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