In this article, we’ll be sharing with you everything you need to know about the constellation of Aquila, including how to find it, deep space objects contained within it and how to use it to find other night sky objects more easily.
The Constellation of Aquila
Aquila constellation was known to the Ancient Babylonians as an eagle (which is the Latin meaning of Aquila) and to the Ancient Romans as a flying vulture. It is such an obvious shape that Greek astronomer Ptolemy cataloged it more than 2000 years ago.
There are a few Greek myths about this constellation. In one, Aquila is the eagle that carried Zeus’s thunderbolts and also carried Ganymede to Olympus to be the cupbearer of the gods. In a second myth, the eagle guards the arrow of Eros (which is represented by the constellation Sagitta) that hit Zeus and made him love-struck. In a third myth, Aphrodite disguised herself as an eagle and pretended to pursue Zeus (who was disguised as a swan) so that Nemesis (Zeus’s love interest) would shelter Zeus.
To help you spot Aquila, here’s what SkySafari 6 shows.
Aquila has an area of 652 square degrees making it the 22nd largest of the 88 recognized constellations.
Aquila is usually depicted as an eagle with a long body and v-shaped wings. The brightest star in Aquila is Altair, properly known as Alpha Lyrae. Altair is the second brightest of the three stars forming the Summer Triangle asterism, the others being Vega (Alpha Lyrae) and Deneb (Alpha Cygni).
Altair, Alshain, and Tarazed (Alpha, Beta, and Gamma Aquilae) form a straight line ~5° long and this asterism is known to Indigenous peoples in Australia. In their myths, Altair represents a male spirit and Alschain and Tarazed either represent his two wives or the feather decorations on his arms.
In the next section discover how to find Aquila.
How To Find Aquila In The Night Sky
Aquila is part of the Hercules family of constellations and is an equatorial constellation. It’s visible to observers at latitudes between +90° and -75°. It’s also an equatorial constellation. Both Northern and Southern Hemisphere observers can see it from July to November in the evening, with September being the best month to view it.
The constellation of Aquila is bordered by the constellations Aquarius, Capricornus, Delphinus, Hercules, Ophiuchus, Sagitta, Sagittarius, Scutum, and Serpens Cauda.
To find Aquila, do a naked-eye search for the Summer Triangle. Altair marks the southern apex of the Summer Triangle and Aquila is opposite Cygnus.
To find Aquila’s exact position for your location on any night, use software such as Stellarium (free) or SkySafari.
Aquila’s Brightest Stars
Aquila contains 20 stars that shine at magnitude 5 or brighter. The star chart below, from SkySafari 6, shows these for reference. The more interesting ones are listed below the chart with more detail.
Alpha Aquilae (Altair) – This double star is the brightest star in Aquila and the 13th brightest star in the night sky. The magnitude 0.93, yellow-white, main-sequence, primary and magnitude 9.72, secondary component are 165.2 arcseconds apart. It’s 16.8 light-years away. ‘Altair’ means ‘the flying eagle’ in Arabic.
Beta Aquilae (Alshain) – This variable double star is the seventh brightest star in Aquila. The magnitude 3.72, yellow-orange subgiant, primary and magnitude 11.40, secondary component are 13.4 arcseconds apart. Alshain is an eruptive variable ranging in magnitude from 3.68 to 3.74. It’s 45 light-years away.
Gamma Aquilae (Tarazed) – This variable double star is the second brightest star in Aquila. The magnitude 2.71, orange-red, bright giant, primary and magnitude 12.15, secondary component are 131.4 arcseconds apart. Tarazed is an eruptive variable with a 2.72 minimum magnitude. It’s 460 light-years away. ‘Tarazed’ means ‘The Beam of the Scale’ in Persian.
Delta Aquilae – This variable double star is the fifth brightest star in Aquila and is 50 light-years away. The magnitude 3.36, yellow-white subgiant, primary and magnitude 12.75, secondary component are 137.0 arcseconds apart. This eruptive variable ranges in magnitude from 3.34 to 3.38.
Epsilon Aquilae (Deneb al Okab) – This double star forms part of the tail of the eagle and is 154 light-years away. The magnitude 4.01, orange giant, primary and magnitude 10.56, secondary component are 0.0 arcseconds apart. ‘Deneb al Okab’ means ‘the tail of the eagle’ in Arabic.
Zeta Aquilae (Deneb al Okab) – This variable double star is the third brightest star in Aquila. Zeta Aquilae is also known as Deneb al Okab and also forms the eagle’s tail feathers. The magnitude 2.99, white, main-sequence, primary and magnitude 12.00, secondary component are 7.2 arcseconds apart. This eruptive variable ranges in magnitude from 2.98 to 2.99. It’s 83 light-years away.
Eta Aquilae – This variable double star is 1170 light-years away. The magnitude 3.86, yellow supergiant primary, and its secondary components are 0.7 arcseconds apart. This pulsating variable ranges in magnitude from 3.48 to 4.33 over 7.1769 days. It’s one of the most prominent Cepheid variables. Eta Aquilae is ~1° north of the celestial equator.
Theta Aquilae (Tseen Foo) – This variable double star is the fourth brightest star in Aquila. The magnitude 3.25, blue-white giant primary, and magnitude 13.00 secondary components are 115.8 arcseconds apart. This eruptive variable has a minimum magnitude of 3.23. Theta Aquilae is 286 light-years away. ‘Tseen Foo’ is derived from the Mandarin word for ‘The heavenly rafter’ and ‘drumsticks’. This may be a multiple system.
Iota Aquilae – This variable double star is 391 light-years away. The magnitude 4.36 blue-white giant primary, and magnitude 13.00 secondary components are 45.4 arcseconds apart. This eruptive variable has a minimum magnitude of 4.35. This may be a multiple system.
Kappa Aquilae – This magnitude 4.96, blue-white giant star is 1,681 light-years away. It’s an eruptive variable that ranges in magnitude from 4.96 to 4.98.
Lambda Aquilae – This double star is the sixth brightest star in Aquila. The magnitude 3.44 blue-white main-sequence primary, and its secondary components are 14.7 arcseconds apart. It’s 124 light-years away. This may be a multiple system.
Mu Aquilae – This variable double star is 108 light-years away. The magnitude 4.44, orange giant, primary and magnitude 13.10, secondary component are 56.2 arcseconds apart. This eruptive variable ranges in magnitude from 4.42 to 4.46. This may be a multiple system.
Nu Aquilae – This variable double star is 2836 light-years away. The magnitude 4.67, yellow supergiant, primary and magnitude 9.47, secondary component are 200.5 arcseconds apart. This eruptive variable ranges in magnitude from 4.62 to 4.69. This may be a multiple system.
Xi Aquilae (Libertas) – This double star is 184 light-years away. The magnitude 4.71 orange giant primary, and its secondary component are 0.1 arcseconds apart. ‘Libertas’ is Latin for ‘liberty’. Xi Aquilae has a planetary companion known as Xi Aquilae b or ‘Fortitudo’ (Latin for ‘Fortitude’).
Rho Aquilae – This magnitude 4.94, white, main-sequence star is 150 light-years away. Its mass is 2.5 Solar masses, its diameter is 1.9 Solar diameters and it’s 1.6 times hotter than the Sun.
Star Hopping From Aquila
Aquila is the starting point for a couple of well-known star hops.
M11 – To find the Wild Duck Cluster (M11) from Aquila, first identify Altair. From there, hop ~8° southwest to Delta Aquilae, ~9° southwest to Lambda Aquilae, and then ~4° south-southwest to M11.
Alternatively, identify Altair. Hop ~8° southwest to Delta Aquilae, then extend the line ~16° southwest to the 0.31 arcminute semicircle of M11.
NGC 6709 – Identify Epsilon Aquilae. Hop ~5° southwest to NGC 6709.
Objects To See Within Aquila
Aquila contains no Messier objects but it does have some other deep sky objects suitable for small telescope users.
NGC 6709 – This open cluster has a magnitude of 6.69 and an apparent size of 14.0 arcminutes. It’s 3.5 thousand light-years away and is at right ascension 18h 52m 22s and declination 10° 20’ 34”.
NGC 6738 – This open cluster has a magnitude of 8.3 and an apparent size of 15.0 arcminutes. It’s 2300 light-years away and is at right ascension 19h 02m 24s and declination 01° 37’ 54”.
NGC 6760 – This globular cluster has a magnitude of 8.88 and an apparent size of 9.6 arcminutes. It’s 24 thousand light-years away and is at right ascension 19h 12m 21s and declination 01° 04’ 02”.
Summary
Aquila is the 22nd largest constellation and contains some notable stars and deep sky objects for small telescope users. Look for it south of the Summer Triangle this summer.
