Galaxy Arm

Honourable mention in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.

Taken from the south of Iraq in January 2022, this image shows a clear sky over one of the many ancient monuments in the region which looks like a Babylonian ziggurat. The Sumerians had invented these mountain-like buildings even before the invention of script; the earliest ziggurats appear around 4000 years before the common era. They look like the frustum of a pyramid and in Babylonian times often had temples on top. Next to the stairs of the ziggurat are the constellations of the southernmost part of the Zodiac, also invented in Babylon. Today, we call them Capricorn (left, with a planet in it) and Sagittarius, whose brightest stars form the asterism of the Teapot. For the Babylonians, Sagittarius was the god Pabilsang, the city god of Larak and a god of agriculture and war. He was also the husband of the mighty goddess of medicine, Gula, and his iconography is a hybrid creature holding a bow and arrow: a male human torso and head attached to the body of a horse with four legs, two gigantic wings and two tails — a horse tail and a scorpion tail. Such a creature did not exist in Greek mythology, so the Greeks reduced it to something they knew, a centaur holding a bow and arrow. This picture still did not make sense in Greek culture because centaurs were considered wild and cruel, and not intelligent enough to use a bow and arrow. Therefore, there was another Greek figure that existed simultaneously: a man with hooves instead of feet at the ends of his legs, a satyr, but this figure vanished in Roman times. 

Capricornus is one of the most stable foreign creatures in the Zodiac and has been unchanged over millennia. It is depicted as a hybrid creature with the front part of a goat and the back part of a fish. This so-called Goat-Fish constellation has been recognised since the earliest writings of astronomy in Babylon. In Babylonian religion it is a good-natured, benevolent demon that protects humans, supports all healing processes and accompanies the god of wisdom and witchcraft. The Greeks simply adopted it and invented a saga for it. In Roman times, it became tremendously famous because emperor Augustus of Rome used it as his personal symbol, also imprinting it on coins and other political propaganda tools.

In Sagittarius, there is also the bright bulge of the Milky Way. That this is hardly visible in this photograph is a result of modern civilization; the huge number of artificial lights that we use on Earth also illuminates the night sky and makes it impossible to see the Milky Way in areas where humans live.

Credit: Ruqayah Mohammed/IAU OAE (CC BY 4.0)