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Aquila

Constellation
List of stars in Aquila
Abbreviation	Aql
Genitive	Aquilae[1]
Pronunciation	/ˈækwɪlə/ Áquila, occasionally /əˈkwɪlə/; genitive /ˈækwɪliː/
Symbolism	the Eagle[1]
Right ascension	18h 41m 18.2958s– 20h 38m 23.7231s[2]
Declination	18.6882229°–−11.8664360°[2]
Area	652 sq. deg. (22nd)
Main stars	10[1]
Bayer/Flamsteed stars	65
Stars with planets	9
Stars brighter than 3.00m	3
Stars within 10.00 pc (32.62 ly)	2
Brightest star	Altair (α Aql) (0.76m)
Messier objects	0
Meteor showers	June Aquilids Epsilon Aquilids
Bordering constellations	Sagitta Hercules Ophiuchus Serpens Cauda Scutum Sagittarius Capricornus Aquarius Delphinus
Visible at latitudes between +90° and −75°. Best visible at 21:00 (9 p.m.) during the month of August.

Aquila is a constellation on the celestial equator. Its name is Latin for 'eagle' and it represents the bird that carried Zeus/Jupiter's thunderbolts in Greco-Roman mythology.

Its brightest star, Altair, is one vertex of the Summer Triangle asterism. The constellation is best seen in the northern summer, as it is located along the Milky Way. Because of this location, many clusters and nebulae are found within its borders, but they are dim and galaxies are few.

History

The constellation Aquila as it can be seen by the naked eye

The former constellation Antinous was merged into Aquilla in 1930, but both can be seen in this 1825 chart from Urania's Mirror.

Aquila was one of the 48 constellations described by the second-century astronomer Ptolemy. It had been earlier mentioned by Eudoxus in the fourth century BC and Aratus in the third century BC.^[3]

It is now one of the 88 constellations defined by the International Astronomical Union. The constellation was also known as Vultur volans (the flying vulture) to the Romans, not to be confused with Vultur cadens which was their name for Lyra. It is often held to represent the eagle which held Zeus's/Jupiter's thunderbolts in Greco-Roman mythology. Aquila is also associated with the eagle that kidnapped Ganymede, a son of one of the kings of Troy (associated with Aquarius), to Mount Olympus to serve as cup-bearer to the gods.^[1]

Ptolemy catalogued 19 stars jointly in this constellation and in the now obsolete constellation of Antinous, which was named in the reign of the emperor Hadrian (AD 117–138), but sometimes erroneously attributed to Tycho Brahe, who catalogued 12 stars in Aquila and seven in Antinous. Hevelius determined 23 stars in the first^[4] and 19 in the second.^[4][3]

The Greek Aquila is probably based on the Babylonian constellation of the Eagle, which is located in the same area as the Greek constellation.^[5]

Notable features

Stars

Aquila, which lies in the Milky Way, contains many rich starfields and has been the location of many novae.^[1]

• 
  α Aql (Altair) is the brightest star in this constellation and one of the closest naked-eye stars to Earth at a distance of 17 light-years. Its name comes from the Arabic phrase al-nasr al-tair, meaning "the flying eagle". Altair has a magnitude of 0.76.^[1]
  


• 
  β Aql (Alshain) is a yellow-hued star of magnitude 3.7, 45 light-years from Earth. Its name comes from the Arabic phrase shahin-i tarazu, meaning "the balance"; this name referred to Altair, Alshain, and Tarazed.^[1]
  


• 
  γ Aql (Tarazed) is an orange-hued giant star of magnitude 2.7, 460 light-years from Earth. Its name, like that of Alshain, comes from the Arabic for "the balance".^[1]
  


• 
  ζ Aql (Okab^[6]) is a blue-white-hued star of magnitude 3.0, 83 light-years from Earth.^[1]
  


• 
  η Aql is a yellow-white-hued supergiant star, 1200 light-years from Earth. Among the brightest Cepheid variable stars, it has a minimum magnitude of 4.4 and a maximum magnitude of 3.5 with a period of 7.2 days.^[1]
  


• 
  15 Aql is an optical double star. The primary is an orange-hued giant of magnitude 5.4, 325 light-years from Earth. The secondary is a purple-hued star of magnitude 7.0, 550 light-years from Earth. The pair is easily resolved in small amateur telescopes.^[1]
  


• 
  57 Aql is a binary star. The primary is a blue-hued star of magnitude 5.7 and the secondary is a white star of magnitude 6.5. The system is approximately 350 light-years from Earth; the pair is easily resolved in small amateur telescopes.^[1]
  


• 
  R Aql is a red-hued giant star 690 light-years from Earth. It is a Mira variable with a minimum magnitude of 12.0, a maximum magnitude of 6.0, and a period around 9 months. It has a diameter of 400 D_☉.^[1]
  


• 
  FF Aql is a yellow-white-hued supergiant star, 2500 light-years from Earth. It is a Cepheid variable star with a minimum magnitude of 5.7, a maximum magnitude of 5.2, and a period of 4.5 days.^[1]
  


• 
  ρ Aql moved across the border into neighboring Delphinus in 1992.

Novae

Two major novae have been observed in Aquila; the first one was in 389 BC, and was recorded as being as bright as Venus^{[citation needed]}; the other (Nova Aquilae 1918) briefly shone brighter than Altair, the brightest star in Aquila.

Deep-sky objects

IRAS 19024+0044 is a protoplanetary nebula in Aquila.

Three interesting planetary nebulae lie in Aquila:

• 
  NGC 6804 shows a small but bright ring.


• 
  NGC 6781 bears some resemblance with the Owl Nebula in Ursa Major.


• 
  NGC 6751, also known as the Glowing Eye, is a planetary nebula.

More deep-sky objects:

• 
  NGC 6709 is a loose open cluster containing roughly 40 stars, which range in magnitude from 9 to 11. It is about 3000 light-years from Earth.^[1] It has an overall magnitude of 6.7 and is about 9100 light-years from Earth. NGC 6709 appears in a rich Milky Way star field and is classified as a Shapley class d and Trumpler class III 2 m cluster. These designations mean that it does not have many stars, is loose, does not show greater concentration at the center, and has a moderate range of star magnitudes.^[7]
  


• 
  NGC 6755 is an open cluster of 7.5 m; it is made up of about a dozen stars with magnitudes 12 through 13.


• 
  NGC 6760 is a globular cluster of 9.1 m.


• 
  NGC 6749 is an open cluster.


• 
  NGC 6778 is a planetary nebula.


• 
  NGC 6741 is a planetary nebula.


• 
  NGC 6772 is a planetary nebula.

Aquila also holds some extragalactic objects. One of them is what may be the largest single mass concentration of galaxies in the Universe known, the Hercules–Corona Borealis Great Wall. It was discovered in November 2013, and has the size of 10 billion light years. It is the biggest and the most massive structure in the Universe known.

Other

NASA's Pioneer 11 space probe, which flew by Jupiter and Saturn in the 1970s, is expected to pass near the star Lambda (λ) Aquilae in about 4 million years.^[8]

Illustrations

In illustrations of Aquila that represent it as an eagle, a nearly straight line of three stars symbolizes part of the wings. The center and brightest of these three stars is Altair. The tips of the wings extend further to the southeast and northwest. The head of the eagle stretches off to the southwest.^{[citation needed]}

Mythology

Aquila, with the now-obsolete figure of Antinous, as depicted by Sidney Hall in Urania's Mirror,^[9] a set of constellation cards published in London around 1825. At left is Delphinus.

According to Gavin White, the Babylonian Eagle carried the constellation called the Dead Man in its talons. The author also draws a comparison to the classical stories of Antinous and Ganymede.^[5]

In classical Greek mythology, Aquila was identified as Αετός Δίας (Aetos Dios), the eagle that carried the thunderbolts of Zeus and was sent by him to carry the shepherd boy Ganymede, whom he desired, to Mount Olympus; the constellation of Aquarius is sometimes identified with Ganymede.^[1]

In the Chinese love story of Qi Xi, Niu Lang (Altair) and his two children (β and γ Aquilae) are separated forever from their wife and mother Zhi Nu (Vega), who is on the far side of the river, the Milky Way.^{[citation needed]}

In Hinduism, the constellation Aquila is identified with the half-eagle half-human deity Garuda.^[10][11]

In ancient Egypt, Aquila possibly was seen as the falcon of Horus.^[12] According to Berio, the identification of Aquila as an Egyptian constellation, and not merely Graeco-Babylonian, is corroborated by the Daressy Zodiac.^[13] It depicts an outer ring showing the Sphaera Graeca, the familiar Hellenistic zodiac, while the middle ring depicts the Sphaera Barbarica or foreigner's zodiac with the zodiacal signs of the Egyptian dodekaoros which were also recorded by Teucros of Babylon.^[14] Under the sign of Sagittarius is the falcon of Horus, presumably because Aquila rises with Sagittarius.

Equivalents

In Chinese astronomy, ζ Aql is located within the Heavenly Market Enclosure (天市垣, Tiān Shì Yuán), and the other stars of the constellation are placed within the Black Tortoise of the North (北方玄武, Běi Fāng Xuán Wǔ).

Several different Polynesian equivalents to Aquila as a whole are known. On the island of Futuna, it was called Kau-amonga, meaning "Suspended Burden". Its name references the Futunan name for Orion's belt and sword, Amonga.^[15] In Hawaii, Altair was called Humu, translated to English as "to sew, to bind together parts of a fishhook." "Humu" also refers to the hole by which parts of a hook are bound together.^[16]Humu-ma was said to influence the astrologers.^[17]Pao-toa was the name for the entire constellation in the Marquesas Islands; the name meant "Fatigued Warrior".^[18] Also, Polynesian constellations incorporated the stars of modern Aquila. The Pukapuka constellation Tolu, meaning "three", was made up of Alpha, Beta, and Gamma Aquilae.^[19] Altair was commonly named among Polynesian peoples, as well. The people of Hawaii called it Humu, the people of the Tuamotus called it Tukituki ("Pound with a hammer")^[20] - they named Beta Aquilae Nga Tangata ("The Men")^[21] - and the people of Pukapuka called Altair Turu and used it as a navigational star.^[22] The Māori people named Altair Poutu-te-rangi, "Pillar of the Sky", because of its important position in their cosmology. It was used differently in different Māori calendars, being the star of February and March in one version and March and April in the other. Altair was also the star that ruled the annual sweet potato harvest.^[23]

Namesakes

Two United States Navy ships, USS Aquila (AK-47) and USS Aquila (PHM-4), are named after the constellation.

See also

• Aquila (Chinese astronomy)

References

Citations

References

External links

Wikimedia Commons has media related to: Aquila (category)

• Star Tales – Aquila


• The Deep Photographic Guide to the Constellations: Aquila


• WIKISKY.ORG: Aquila constellation


• Warburg Institute Iconographic Database (over 150 medieval and early modern images of Aquila)

Coordinates: 20^h 00^m 00^s, +05° 00′ 00″