Aquarius is one of the most ancient constellations in the night sky and in most cultures is visualized as a man pouring water from a vessel, hence the Latin translation of its name meaning the “water-carrier”. It is the 10th largest constellation in the night sky, and its brightest star, Sadalsuud, is a yellow supergiant with an apparent magnitude of +2.87.
Mythology: Represents a Water-Bearer
Aquarius depicts a cup bearer pouring water into the mouth of the Southern Fish, which is represented by the constellation Piscis Austrinus. The Greeks believed that Aquarius was Ganymede, the most beautiful boy alive, and the son of King Tros, after whom Troy was named. Even Zeus became infatuated with the boy, and transformed himself into an eagle (Aquila) before carrying him off to mount Olympus to become cup-bearer to the gods. Ganymede often accompanied Zeus on his many travels and impressed with the young boy’s kindness the king of the gods even granted Ganymede’s request to help the people of Earth by allowing him to send down rain. The story of Zeus’s love for Ganymede was popular in Rome, where it was taken as divine sanction for homosexuality.
Location: Southern Constellation
Located almost on the ecliptic, Aquarius can be viewed by observers between latitudes +65° and -90°, where it takes up an area of 980 square degrees of the southern celestial hemisphere. It can be found directly to the east of Cetus, almost due west of Capricornus, and almost due north of Piscis Austrinus. Being a member of the zodiac family the Sun, Moon and planets all regularly travel within its boundaries.
Aquarius’ almost universal association with water may be related to the fact that the Sun enters the constellation when many parts of the world are visited by a rainy season. It is also found in a region of the sky known to the ancient Greeks as the Sea due it containing several water-related constellations, including Capricornus (Sea-goat), Cetus (Whale), Delphinus (Dolphin), Eridanus (Great River), Hydra (Water Serpent), Pisces (Fishes), and Piscis Austrinus (Southern Fish).
Best Seen: Autumn
Aquarius is best seen in the Northern Hemisphere during autumn, or in Southern Hemisphere in spring. In the northern autumn, the constellation appears to be in the southern sky, while during the southern spring it is either high in the northern sky, or even directly overhead, depending on the viewer’s location.
Shape: Series of Triangular Patterns
In terms of shape, it takes a lot of imagination to discern a figure of a man pouring water from a jar. Add to this the fact that it takes a dark night to see all the stars and objects that make up the constellation, and it becomes an even more difficult task to see the whole picture, so to speak. From urban skies, the constellation can best be described as a series of inter-connected triangles.
Notable Stars: Sadalsuud (2nd magnitude)
– Sadalsuud (Beta Aquarii), a yellow supergiant (G0 Ib) located 610 light years from Earth, is the most luminous star in Aquarius with an apparent magnitude of 2.91. It is 50 times bigger and 6 times more massive than the Sun, but 2,200 times brighter, making its Latin name, “Lucida Fortunae Fortunarum” (brightest luck of lucks) particularly apt. Sadalsuud appears to have at least two faint optical companions separated from it by 35.4 and 57.2 arcseconds respectively.
– Sadalmelik (Alpha Aquarii), the second brightest star in Aquaruius, is a pale yellow supergiant (G2 Ib) about 760 light years from our solar system than shines with an apparent magnitude of 2.95. This 53 million year old star is around 77 times bigger than the Sun, with 6.5 times its mass, and at least 3,000 times its brightness. Sadalmelikderives from the Arabicmeaning “Luck of the king”.
– Skat (Delta Aquarii), the constellation’s third most luminous star, is a blue dwarf (A3V) found about 160 light years away of magnitude of 3.3. It has around twice the Sun‘s size and mass, with 26 times its brightness. Delta Aquarii is thought to be a member of Collinder 285, also known as the Ursa Major Moving Group, an association of stars that includes many of the principal stars of Ursa Major.
Other stars of interest in Aquarius includes the blue subgiant Albali; the blue-white subgiant Eta Aquarii; the blue-white subdwarf Omega-2 Aquarii; the blue-white subdwarf Iota Aquarii; the white subgiant Omega-1 Aquarii the yellow giant Nu Aquarii; the yellow-white subdwarf Ancha; the orange giants Tau-2 Aquarii and Situla; the red giant Lambda Aquarii; and the red dwarfs Gliese 849 and Gliese 876.
Notable Objects: Contains the Eye of God
The constellation of Aquarius contains three Messier objects, including the globular clusters M2 and M72, and M73, which is an asterism of four unconnected stars that form a “Y” shape in the sky. It also contains a nuber of other interesting objects, such as the Saturn Nebula (NGC 7009), The Aquarius Dwarf galaxy, the Atoms for Peace Galaxy (NGC 7252), and the spiral galaxy NGC 7727.
–The Helix Nebula (NGC 7293, Caldwell 63), located just 700 light years away, is one of the most luminous planetary nebulae closest to Earth. Due to its resemblance to an eye, and no doubt its impressive size (2.5 light years) the Helix Nebula was given the nickname, “The Eye of God”. Look for the “Eye of God” about one degree to the westward of Upsilon Aquarii; however, small telescopes will only reveal a fuzzy patch, but larger instruments (6” and above) will reveal a distinct dark patch with a bright star in the centre.
– Messier 2 (M2, NGC 7089) is not only one of the oldest known globular clusters with an estimated age of 13 billion years; it also one of the largest globular clusters ever discovered, spanning an area of 175 light years. However, M2 is relatively sparsely populated, containing only about 150,000 stars, among which are 21 known variable stars. M2 is about 37,500 light years away, and with an apparent visual magnitude of 6.3, it can be a challenging target for small telescopes from urban areas.
– The Aquarius Dwarf (PGC 65367, DDO 210) is an irregular dwarf galaxy located about 3.1 million light years away that forms part of the Local Group of Galaxies. It is however, a rare example of a galaxy that displays a distinct blue-shift, meaning that is approaching the Milky Way at a rather brisk pace- all of 137 km/sec. This galaxy has an apparent magnitude of 14.0.
Meteor Showers: Delta Aquarid (+3 others)
During the months of July and August, the Aquarid-Capricornid meteor shower becomes active, with several confusing meteor streams peaking at different times, making it difficult to tell which shower is in progress at the time of viewing. Moreover, some of the streams are divided into northern and southern branches, confusing the issue even further. In addition, none of the various streams are very productive, but for the benefit of readers that are inclined to observe the various meteor streams in this complex, the peak dates are given below”
– The March Aquariids runs during the month of March, with a peak between the 11th and 12th when observers can expect to see between 3 and 7 meteors per hour.
– The Eta Aquariids runs from April 21st to about May 12th, with a peak on the night of May 5th/6th when northern hemisphere observers can see up to 10 meteors per hour, while in the southern hemisphere observers can expect to see around 30 meteors per hour.
– The Delta Aquariids is the largest meteor shower associated with Aquarius, and runs from July 14th to 18th, with a peak on the night of August 13th/14th. This shower is best seen from the southern hemisphere, since the radiant does not rise much above the horizon for northern observers. Southern observers can expect to see between 15 and 20 meteors per hour at the peak.
– The Iota Aquariids consists of at least four diffuse, and widely separated radiant’s, making observation of this stream difficult, if not confusing. The two main streams of this shower cover the times from July 1st to September 18th for the southern branch, and August 11th to September 10th for the northern branch. Maximum rates are 7-8 meteors per hour, and 5-10 meteors per hour respectively.
Planets: 14 Stars with Planets
Aquarius has 14 stars with confirmed planets, of which one star, Gliese 876, has four planets orbiting it. Its inner-most planet is believed to be either a small, Neptune-type planet, or alternatively a large, rocky Earth-like variety, with investigations into its true nature still ongoing. The two middle planets are about the same size and mass as Jupiter, while the outer-most planet is about as massive as Uranus. The three outer planets are also locked into a Laplace (1: 2: 4) resonance, just like three of Jupiter’s moons- Ganymede, Europa, and Io.
In astrology, the Sun passes through the sign of Aquarius from January 20th to February 18th. Due to precession, however, the Sun currently passes in front of the constellation Aquarius from about February 16th to March 12th, which is roughly a month later. Other astrological associations are:
Date of Birth: Jan 20 to Feb 18
Sign Ruler: Uranus
Birth Stone: Amethyst, Blue Obsidian, Garnet
Characteristics: Original, tolerant, charitable, independent, practical
Compatibility: Gemini, Libra and Aquarius
Other Mythological Lore
In classical Greek mythology, Aquarius is sometimes associated with Ganymede, but other accounts associate the constellation with Deucalion, the son of Prometheus, who managed to escape the flood sent by Zeus to punish mankind for its sins. Being a favourite of Zeus, the supreme god warned Deucalion of the impending disaster, and advised him to build an ark, and to also take his wife Pyrrha onboard so that they might escape the flood.
In ancient Egyptian accounts, Aquarius is associated with Hapi, the benevolent god of the Nile River who caused the Nile to flood every year, thereby sustaining the people. In Egyptian depictions, Aquarius as the Water Bearer is almost always shown holding the Norma Nilotica, a device used by the god Hapi to measure the depth of the Nile River.