Aquarius: The Water Bearer

Aquarius is a large but relatively faint zodiac constellation that occupies a region of sky sometimes called the Sea, alongside other water-themed constellations like Pisces, Cetus, and Capricornus. Although it lacks very bright stars, Aquarius contains some remarkable deep sky objects and holds deep mythological significance across many cultures. Locate it with StarGlobe.

How to Find Aquarius

Aquarius is best found using the Summer Triangle as a starting point. From Altair in Aquila, look about 25 degrees to the south-southeast. The most identifiable feature in Aquarius is the Water Jar (or Y-shaped asterism), a small group of four stars forming the container from which the water bearer pours. This compact pattern is easier to spot than the constellation's other scattered stars.

Another approach is to find the Great Square of Pegasus and look below its eastern edge. Aquarius sprawls across the space between Pegasus to the north and Fomalhaut in Piscis Austrinus to the south.

The constellation's stars are mostly third and fourth magnitude, so reasonably dark skies are helpful for tracing the full figure. The water bearer is depicted pouring water from the jar, with a stream of faint stars flowing southward toward the mouth of the Southern Fish, where Fomalhaut represents the fish drinking the water.

The Stars of Aquarius

Sadalsuud (Beta Aquarii) is the brightest star in the constellation at magnitude 2.9. It is a yellow supergiant about 540 light-years away. Its name comes from Arabic and translates roughly as "the luckiest of the lucky." Sadalmelik (Alpha Aquarii) is a similar yellow supergiant at magnitude 2.95, and its name means "luck of the king."

The Water Jar asterism consists of Gamma, Zeta, Eta, and Pi Aquarii. Zeta Aquarii is a close binary star resolvable in small telescopes, with two nearly equal components orbiting each other over about 760 years.

Skat (Delta Aquarii) marks a point along the stream of water flowing from the jar. It is a white main-sequence star about 113 light-years away and is associated with the radiant of the Delta Aquariid meteor shower.

Deep Sky Objects

The Helix Nebula (NGC 7293) is the closest planetary nebula to Earth at roughly 650 light-years. It is also one of the largest in apparent size, spanning about half the width of the full Moon. Under very dark skies with a nebula filter, it appears as a ghostly ring. Long-exposure images reveal its famous "Eye of God" appearance, with intricate filaments and a hot central star illuminating the expanding gas.

The Saturn Nebula (NGC 7009) is a smaller but brighter planetary nebula named for the faint extensions on either side that resemble Saturn's rings when viewed through a telescope. It shines with a distinctive greenish-blue color at magnitude 8.0, making it visible in small telescopes.

M2 is a bright globular cluster in Aquarius, one of the largest and richest globulars in the sky at about 37,000 light-years from Earth. It is a fine target in binoculars and begins to resolve into individual stars with a 6-inch or larger telescope. M72, a more distant and fainter globular, and M73, a sparse group of four stars, are also within the constellation.

Mythology and Cultural Heritage

In Greek mythology, Aquarius is often associated with Ganymede, a handsome Trojan youth who was carried to Olympus by Zeus (in the form of an eagle, represented by Aquila) to serve as cup-bearer to the gods. The constellation depicts him pouring water or nectar from his vessel.

Other traditions connect Aquarius to Deucalion, the Greek equivalent of Noah, who survived a great flood. Babylonian mythology associated the constellation with Ea, the god of water and wisdom, who poured life-giving waters upon the land. In Egyptian astronomy, the rising of Aquarius coincided with the annual flooding of the Nile, the essential event that brought fertility to the land.

The phrase "Age of Aquarius," popularized in the 1960s, refers to the slow precession of the equinoxes that will eventually shift the vernal equinox into Aquarius, though astronomers disagree on exactly when this transition occurs.

Best Time to Observe

Aquarius is best observed during September and October evenings, when it crosses the meridian during convenient hours. The constellation is relatively low in the southern sky for Northern Hemisphere observers and can be partially obscured by horizon haze. From the Southern Hemisphere, Aquarius rides higher and is easier to observe in its entirety.

The Delta Aquariid meteor shower peaks in late July, producing about 15 to 20 meteors per hour. The Eta Aquariid shower, which peaks in early May, is caused by debris from Halley's Comet and is best seen from the Southern Hemisphere.

Neighboring Constellations

Capricornus lies to the west, while Pisces borders Aquarius to the north and east. Pegasus is above to the north. Piscis Austrinus with Fomalhaut sits directly south, and Cetus stretches to the southeast. Sculptor and Aquila bound the constellation to the south and northwest respectively. Explore the autumn Water region with StarGlobe.

Quick Facts

Aquarius covers 980 square degrees, ranking 10th in size. It contains three Messier objects (M2, M72, M73). Its brightest star, Sadalsuud, shines at magnitude 2.9. The constellation's right ascension ranges from about 20h 38m to 23h 56m, and its declination spans from about -25 to +3 degrees.