Aquarius - The Water Bearer

Aquarius is a large, fall constellation for northern observers. For southern observers it a spring constellation. Its stars are scattered, and some of them form groupings or asterisms. Aquarius is best seen from August through October. It rises above the southern horizon on autumn evenings, and lies between Pisces and Capricorn.

The stars of this group are comparatively faint, and it requires some imagination to see the figure of a man on his knees pouring water from a jar. The asterism easiest to spot is the water jar that Aquarius is holding. If you follow an imaginary line drawn through Scheat and Markab in the square of Pegasus, to a point below the circlet of Pisces, then look a little to the right, you can see the Y-shaped figure marking the water jar.

The constellations near Aquarius are associated with water and the sea, such as Cetus the Whale, Pisces the fish, and Capricorn the Sea Goat.

Each year there are two meteor showers in Aquarius. The first is the Eta Aquarids, which produces about 20 meteors each hour around May 4th. The second, the Delta Aquarids, produces up to 20 meteors each hour about July 28th.

History and Mythology

Aquarius is the 12th sign of the zodiac, and the whole area was associated with water and rain in ancient times. The Chinese and Indian calendars list Aquarius as the first constellation because of its association with water. It is one of the most ancient constellations. The figure was sometimes identified as Zeus pouring waters of life from the heavens.

Aquarius also has an association with a very old Sumerian myth of a global deluge. It was thought to be the story that gives rise to the biblical story of the Flood. Several stars' names in Aquarius refer to good luck, probably because in ancient times the constellation's rising occurred at the start of the rainy season, and seemed to bring relief to the dry climates of the Middle East. The early Egyptians believed that its appearance over the horizon with the sun brought fertility to the land.

In the 1960's there was talk of the "dawning of the age of Aquarius", referring to the fact that shortly the Sun will be in Aquarius on the first day of spring. The Aquarian age will actually begin in about 600 years, in the 27th century.

Notable Stars

Aquarius contains about 100 stars that can be seen with the naked eye. The two brightest are Sadalmelik and Sadalsuud. Sadalmelik, or Alpha Aquarii, which is Arabic for "lucky one of the king", is a 2.96 magnitude star located 680 light-years away. Sadalsuud, or Beta Aquarii, is Arabic for "Luckiest of the Lucky," and it is a 2.91 magnitude star 710 light-years away. Fourth-magnitude Sadachbia, Gamma Aquarii, has an older Arabic name meaning "the lucky star of the tents", and is about 160 light years distant.

This large group contains several double stars of note, especially Zeta Aquarii, which is a close binary with a separation of 1.7 arcseconds. It has nearly-identical white components of magnitude 4.4 and 4.6 and lies 103 light years away.

Much closer to home, Luyten 789-6 is a triple star system 11.3 light years from the Sun. All three components are very dim red dwarfs; with a combined magnitude of 12.9, they are much too faint to see except with large telescopes.

Clusters, Nebulae, and Galaxies

There are two globular clusters visible with amateur telescopes in Aquarius. M 2 is a good object for small telescopes. It is located a few degrees north of the star Sadalsuud. M 72 is a less-prominent, 10th magnitude globular cluster. M 73 is not a true star cluster, but an asterism of four faint stars close to M 72 that Charles Messier mistook for a nebulous object with his small telescope.

Aquarius has two planetary nebulae of note, the bright Saturn Nebula (NGC 7009) and the Helix Nebula (NGC 7293), the largest of the planetary nebulae. The Saturn Nebula's outer shell looks like a faint ringed planet in a small telescope.

The large but faint Helix Nebula is located in southern Aquarius. When viewed with binoculars on a clear, dark night it appears like a large, dim smoke ring. In photographs, the Helix Nebula resembles two overlapping rings or a spiral staircase.