Aquila's brightest star, Altair, is part of the Summer Triangle. Many dim clusters and nebula pepper this space-borne eagle.
The constellation of Aquila the Eagle is best seen in the summer as it soars along the Milky Way. Because of its location along the line of our galaxy, many clusters and nebulae are found within its borders, however they are dim and there are few galaxies. In mythology, Aquila was owned by the Roman god Jupiter and performed many tasks for him.
Stars
The brightest star in Aquila is Alpha Aquilae, or Altair. At magnitude 0.76 it is one of the three bright stars marking the corners of the Summer Triangle, with Deneb and Vega being the other two. Altair lies just 16 light-years away from Earth. Two moderately bright stars lie just above and below Altair. Below, or southeast, is Beta Aquilae, also known as Alshain. This magnitude 3.71 star lies 44 light-years away. Just above Altair is Gamma Aquilae, or Tarazed. At magnitude 2.72 it is brighter than Alshain, but lies much farther away at 460 light-years. These stars are usually considered the tail feathers of the eagle. The star marking Aquila's back is Delta Aquilae, at magnitude 3.36 and 50 light-years away. The wing that points to the east-southeast is marked by the star Theta Aquilae at magnitude 3.24; and the wing that points to the north (and Vega) is Zeta Aquilae at magnitude 2.99 and 83 light-years distant. The star usually considered the head of the eagle is Lambda Aquilae at magnitude 3.43 and lies 125 light-years away.
Clusters
While there are no Messier objects in Aquila, there is still a lot to see, especially if you have a big enough telescope. Three globular clusters lie in Aquila and they are NGC 6941, NGC 6749 and NGC 6760. NGC 6941 is the dimmest of these at magnitude 13 and it is found off the end of the wing that points east-southeast. The other two are northwest of a line drawn between Delta Aquilae (the back) and Lambda Aquilae (the head). Closest to that line is NGC 6760, which shines at magnitude 9.1. About two degrees farther away is NGC 6749 at magnitude 11.1. A number of open clusters lie in Aquila, but most of them are faint. The best one to observe is NGC 6755, a 7.5-magnitude grouping found northwest of the star marking the back of the eagle. If you have a good telescope, you can spot NGC 6756 just a half degree away at magnitude 11. Another good open cluster to try for is NGC 6709, which, at magnitude 6.7, can be glimpsed in binoculars. NGC 6709 is about five degrees southwest of Zeta Aquilae, the upper wing of the eagle. In between these two points is yet another cluster, NGC 6738. This sparse cluster is 8th magnitude.
Nebulae
A number of nebulae lie along the line that marks the body of the eagle, but only one is bright enough to reach even 10th magnitude. NGC 6790 lies a little less than two degrees from the star marking the back of the eagle in the direction of its head.
Good luck tracking down these tough-to-spot faint objects in Aquila the Eagle!
