All About The Aquila Constellation 

The night sky provides an amazing canvas on which humans have let loose their imagination since the earliest civilizations—and constellations are perhaps the greatest observable example. Representing legends and myths dating back centuries, they signify humanity's attempt to immortalize stories and culture through means more permanent, and far grander, than themselves.

That being said, it makes sense that stars would serve this purpose, with lifetimes so long to the early astronomer that they appeared unending—and any line envisaged in-between to connect them took only an entitative mind to fill in. That being said, of all the famous constellations in the sky, Aquila is no less storied, and no less grand in its construction. 

Aquila - A Far Earlier Origin

Aquila is the Latin word for Eagle, and reflects the shape attributed to this constellation. It is one of the forty-eight constellations that can be found in Greek-Egyptian astronomer Ptolemy’s 2nd century work, Almagest. This work is one of the earliest recordings of those constellations that arise from the Greco-Roman traditions, and documents a good example of how ‘old’ many of the eighty-eight currently recognized constellations are.

Interestingly enough, the reason for the large difference in the number of constellations is due to the limitations of global-travel in the ancient world. The inhabitants of the Mediterranean at that time were limited in their view of the sky, only able to view a small portion, and it wouldn’t be until the age of exploration after the 1400’s that the European explorers would add new constellations from the Southern Hemisphere to Western lexicon.  

Despite Aquila’s Greek name and associated myths, there is reason to believe the constellation’s history dates back even further. Prior to Ptolemy, the Greek didactic poet Aratus referenced the constellation in his 3rd century work, and it is also known that the Greek astronomer Eudoxus of Cnidus documented the constellation in the 4th century as well—though all of Eudoxus’ works are lost and we only know this through commentaries on his work written by later scholars. While this is as far back as the written record goes, it is generally believed that Aquila’s history predates these writers significantly—perhaps having a Babylonian or even pre-historic origin.

By Till Credner - Own work: AlltheSky.com

The Makings of Myth

In Greek tradition, the Aquila constellation represents Aetos Dios, the Eagle of Zeus who carried his lightning bolts. That same meaning carries over into the Roman tradition, where Zeus is referred to as Jupiter. That said, another story associated with the Eagle is his quest to find the Trojan shepherd boy Ganymede for Zeus—who desired him to be the wine-pourer for the gods. This story is reflected in the constellation's closeness to Aquarius, the representation of Ganymede, and a reason for its name. 

Another myth centered around Aquila is that of the arrow of Eros, represented by the nearby constellation Sagitta (or, the arrow)—which the eagle guarded before it was used against Zeus to make him fall in love. In a dark twist, another myth had the arrow, represented by Sagitta, used by Hercules to kill Aquila. Between Aquila, Sagitta, and Aquarius, there is an immense amount of history as well as mythology in their shared region of the sky.  

Easy to Distinguish Characteristics and Nearby Points of Interest

Outside of myth, Aquila has plenty of features which may interest an amateur astronomer.  Its brightest star is called Altair—known as the twelfth brightest star in the night sky and one of the closest stars to Earth that can be seen by the naked eye.  That said, the star itself is a curious one. An A-Type main-sequence star (also known as a hydrogen-fusing dwarf)—both of its poles are flattened, due to its rapid rotations depressing what would otherwise be its spherical shape.   

The name Altair dates back to the middle ages, and comes from the Arabic phrase al-nasr al-tair—meaning: ‘the flying Eagle.’ Such an origin is a testament to the cross-cultural nature of both the ancient/medieval world, and astronomy as a science. This is further represented in the names of other stars in the constellation, such as Alshain and Tarazed, both of which come from the Arabic phrase shahin-i tarazu—meaning: ‘the balance.’  

There are also several fascinating deep space objects in Aquila’s region of space. The Phantom Streak Nebula, classified with the designation NGC 6741, is an interesting example of a planetary nebula. A massive space of illuminated gas and dust, the planetary nebula is the result of a star shedding its outer layers into a large mass that merely resembles a nebula. Additionally, The Glowing Eye Nebula, or NGC 6751, is another interesting planetary nebula. Formed in the same manner as NGV 6741, this planetary nebula is an easy target for deep-sky observers, so any amateur astronomer should add it to their list.  

An interesting note to make here is that planetary nebulae, despite their name, actually have nothing to do with planets. The term dates back to the 18th century when astronomers incorrectly assumed the glowing clouds of gas they observed were Jovian planets (the technical term for gas-giants). This goes to show how the limitations of available technology can impact our understanding of the universe.   

One last interesting phenomenon from the Aquila constellation is that a nova that was observed in 1918. A nova, not to be confused with a supernova, is a transient astronomical event that results in the sudden, but temporary appearance of a bright ‘new’ star in the sky. This is caused by a binary star system where one star is a white dwarf and the other is either a main-sequence, subgiant, or red giant star. When the pair draw too close together, the white dwarf begins to siphon off hydrogen gases from its partner. This sudden influx of fuel results in rapid runaway fusion, where the energy released is so great that the excess material is blown away from the star. This massive corona of gas is illuminated, causing the appearance of a new star. In 1918, a nova event created an object in the sky brighter than Altair for over a week.