Night Sky Photography -- 09-15-2022 -- The Great Square Of Pegasus & Jupiter In September

For the month of September the planet Jupiter -- which is slowly moving closer to its opposition to the Earth on the evening of Monday, September 26th -- can be used to help any amateur stargazer locate one of the more interesting seasonal asterisms in the night sky: the Great Square of Pegasus. 

 

The Great Square is -- well just what the name implies -- a square of somewhat moderately medium-bright stars set in a roughly 20 degree radius (or about the length of your hand from the end of your extended arm) that makes up a large majority of the Constellation Pegasus the Winged Horse.

This is the photo I took very early last night (or this morning depending on how y'all view it) of the Great Square between the trees in my back yard. Unfortunately due to light pollution, catching the other fainter stars in the entire constellation was next to impossible, but I was able to capture the asterism itself without a problem.

The star in the Great Square closest to the horizon is the magnitude 2.8 star, Algenib (Gamma Pegasi) and also the farthest star from out own Sun at a whopping 333 light-years away.

The star on the opposite corner of the square from Algenib is Scheat (Beta Pegasi), a magnitude 2.4 red-giant star that sits about 199 light-years away.

To the south, the third star in the square is Markab (Alpha Pegasi) at a magnitude 2.5 star and a distance of 140 light-years.

The final star that makes up the square is Alpheratz (Alpha Andromedae), the brightest of the four stars at a magnitude of 2.1 which lies about 97 light-years away. Alpheratz is actually a part of the Constellation Andromeda and serves as its brightest star.

One interesting detail about the Great Square is that it points the way for any amateur astrologist to easily locate the Andromeda Galaxy. Follow a straight line from Alpheratz to a point halfway across the length of the Constellation Andromeda and -- using a really good lens -- you can find the Andromeda Galaxy just slightly above the central stars of the constellation.

Unfortunately, due to light pollution from the nearby Waning Gibbous Moon, capturing the Andromeda Galaxy, or the fainter stars of the Andromeda Constellation this evening was a bust. I might try again in a few nights, clear skies permitting.