Aquarius—Latin for “water-bearer”—is a large but surprisingly faint constellation of the zodiac, lying between Capricornus and Pisces. It is the 10th-largest of the 88 constellations, yet none of its stars is particularly bright, making Aquarius much harder to recognize than neighboring constellations with more obvious stellar patterns.
Its most recognizable feature is a small group of stars known as the Water Jar, while each May, the Eta Aquariid meteor shower appears to radiate from this part of the sky, produced by debris shed from Halley’s Comet. Aquarius also lies among several other water-related constellations in a region traditionally known as the Sea, fitting an association with water that stretches back to some of the earliest recorded astronomical traditions.
Find Aquarius Between a Bright Star and a Great Square
Aquarius is best seen from the Northern Hemisphere during late summer and autumn, with September and October particularly good months for finding it in the evening sky. From the Southern Hemisphere, it is well placed during spring. The constellation is visible from roughly 65° north to 90° south, although dark skies make a considerable difference because most of its stars are relatively faint.
Because Aquarius has no especially bright stars, there’s no obvious star trail leading directly to it as there is for some other constellations. Instead, the easiest approach is to use two brighter landmarks. Look first for the Great Square of Pegasus, a large four-star pattern prominent in the northern autumn sky, and then, well to the south of the Square, for bright blue-white Fomalhaut. Aquarius fills the much fainter stretch of sky in between. Look roughly halfway between the Square and Fomalhaut for the small, Y-shaped Water Jar asterism—that’s the best place to start.
Once you’ve spotted the Water Jar, don’t worry about tracing the Water-Bearer’s much fainter outline. Finding the Jar is enough to know you’re in Aquarius.
Aquarius Holds a Water Jar That Seems to Pour Stars
The Water Jar is formed by four stars—Sadachbia (Gamma Aquarii), Pi Aquarii, Eta Aquarii and Zeta Aquarii. From this small Y-shaped pattern, a winding line of fainter stars extends southward, traditionally representing water pouring from the Water-Bearer’s jar.
The stream leads toward Piscis Austrinus, the Southern Fish, where bright Fomalhaut marks the fish’s mouth. In traditional depictions, the water from Aquarius flows toward the Southern Fish, helping turn what otherwise looks like a scattering of faint stars into a much more understandable celestial scene.
These same stars haven’t always represented a water jar. In traditional Arabic astronomy, the group was associated with an asterism known as al-Akhbiyah, or the Tents. A trace of that older interpretation survives in the name Sadachbia, which is generally translated as the “luck of the tents.”
Two Yellow Supergiants Outshine the Rest of Aquarius
Aquarius’s brightest star is Sadalsuud (Beta Aquarii), a yellow supergiant roughly 540 light-years away. At magnitude 2.9, it is relatively faint for a constellation’s brightest star, helping explain why Aquarius can be difficult to pick out. Despite its Beta designation, Sadalsuud is slightly brighter than Alpha Aquarii.
That Alpha star is Sadalmelik, another yellow supergiant lying roughly 520 light-years from Earth. The two stars are similar in both color and physical nature, but their traditional names provide an even more interesting connection. Sadalsuud’s Arabic name is commonly interpreted as the “luck of lucks” or “luckiest of the lucky,” while Sadalmelik means the “luck of the king.”
The pattern extends beyond the pair. Sadachbia, which we encountered in the Water Jar, has a name meaning the “luck of the tents,” while other traditional star names in this part of the sky also preserve associations with good fortune. Exactly why so many stars here acquired “lucky” names isn’t entirely clear, leaving Aquarius with a curious linguistic legacy whose original meaning has partly been lost.
Five Stars Define the Water-Bearer’s Main Pattern
Five stars provide a useful guide to Aquarius’s main pattern:
- Sadalsuud (Beta Aquarii) — Aquarius’s brightest star, a yellow supergiant with an apparent magnitude of about 2.9.
- Sadalmelik (Alpha Aquarii) — the constellation’s second-brightest star, another yellow supergiant almost as bright as Sadalsuud.
- Skat (Delta Aquarii) — Aquarius’s third-brightest star, a white A-type main-sequence star roughly 160 light-years away. Skat is also considered a likely member of the Ursa Major Moving Group, a widely scattered family of stars that includes five of the seven main stars of the Big Dipper.
- Sadachbia (Gamma Aquarii) — a blue-white main-sequence star about 160 light-years away and one of the four stars forming the Water Jar.
- Zeta Aquarii — a triple-star system about 95 light-years away at the center of the Water Jar. To the unaided eye it appears as a single point of light, but a telescope can separate its two principal stars into a close pair.
Seven Earth-Sized Worlds Orbiting One Tiny Star
One of the most remarkable stars within Aquarius is invisible to the unaided eye. TRAPPIST-1, roughly 40 light-years away, is an ultracool red dwarf only a little larger than Jupiter. Yet this tiny star is orbited by seven Earth-sized rocky planets, packed so tightly together that all seven of their orbits would fit inside Mercury’s orbit around the Sun.
Three of the planets orbit within the star’s habitable zone, where conditions could potentially allow liquid water to exist on a rocky planet with a suitable atmosphere. That doesn’t mean any of them is inhabited—or even necessarily habitable—but having seven Earth-sized rocky worlds around the same nearby star gives astronomers an unusual opportunity to compare planets that formed within a single system.
The contrast with Aquarius’s brightest stars is striking. Sadalsuud and Sadalmelik are enormous supergiants visible across hundreds of light-years, while this tiny, invisible red dwarf hosts one of the most remarkable planetary systems yet discovered.
The “Eye of God” Nebula Watches From Aquarius
The Helix Nebula (NGC 7293) is Aquarius’s best-known deep-sky object and, at roughly 650 light-years away, one of the nearest planetary nebulae to Earth. Despite the name, a planetary nebula has nothing to do with planets. Early telescopes made some of these objects resemble the disks of distant planets, and the misleading name stuck. In reality, a planetary nebula forms when a Sun-like star reaches the end of its life and sheds its outer layers into space, leaving behind its hot, dense core as a white dwarf.
The Helix is sometimes nicknamed the “Eye of God” or “Eye of Sauron” because of its striking eye-like appearance in photographs. High-resolution images reveal thousands of dense knots of gas within the nebula, many with long tails extending away from the central star.
Aquarius also contains Messier 2 (M2), one of the larger globular clusters in the Milky Way. It spans more than 150 light-years and contains around 150,000 stars. The Saturn Nebula (NGC 7009) is another planetary nebula in Aquarius, named for the Saturn-like appearance produced by its elongated shape and extended lobes when seen through larger telescopes.
Two additional Messier objects, the globular cluster M72 and the small asterism M73, also lie within Aquarius.
You can explore these and other targets in our guide to deep-sky objects in Aquarius.
Halley’s Comet Trail Lights Up Aquarius Every May
Aquarius is the radiant point for two annual meteor showers, the best known being the Eta Aquariids, which peak in early May. The meteors are tiny pieces of dust and rock shed by Halley’s Comet and left along its orbit, which Earth encounters each year. They strike Earth’s atmosphere at around 65 kilometers (40 miles) per second, and their high speed can produce glowing trains that linger briefly after the meteor itself has disappeared. Under favorable dark skies, around 50 meteors per hour may be visible near the shower’s peak, with the best views generally coming from the Southern Hemisphere.
The shower takes its name from Eta Aquarii, one of the four stars in the Water Jar, because the meteors appear to radiate from that part of Aquarius. The star isn’t actually producing them—the radiant is simply a perspective effect created as Earth encounters the stream of comet debris. Halley’s Comet produces another familiar meteor shower six months later: Earth crosses its debris again in October, when the meteors appear to radiate from Orion and become the Orionids.
Aquarius also gives its name to the Southern Delta Aquariids, which peak around late July and are generally fainter and slower than the Eta Aquariids. Their radiant lies near Skat (Delta Aquarii), which gives the shower its name, while Comet 96P/Machholz is considered the suspected source of the debris.
Aquarius Lies Among a Sea of Watery Constellations
Aquarius lies in a part of the sky filled with watery figures. Pisces represents the Fishes, Cetus the Sea Monster, Capricornus the Sea-Goat and Piscis Austrinus the Southern Fish. Together with Aquarius, these constellations form part of a region traditionally known as the Sea.
The Water-Bearer’s association with water reaches much further back than Greek mythology. In ancient Mesopotamian astronomy, Aquarius’s predecessor was associated with Ea, or Enki in the earlier Sumerian tradition, a major god connected with freshwater and wisdom who was depicted with streams of water flowing from a vessel. The exact path by which these ancient traditions developed into the constellation we know today is complex, but the combination of a human figure and flowing water has remarkably deep roots.
Greek tradition gave the Water-Bearer a different identity. Aquarius was commonly associated with Ganymede, the beautiful Trojan youth whom Zeus carried to Olympus and made cupbearer to the gods. In this interpretation, the vessel belongs to Ganymede as he pours for the gods, providing a Greek story for a celestial figure whose association with pouring water was already far older.
Modern constellation artwork still depicts Aquarius as a man pouring from a jar, although the stars themselves don’t naturally form an obvious human figure. What observers can recognize is the Water Jar and the stream of stars extending toward the Southern Fish. Together with its place in the Sea and a water-bearing tradition stretching back thousands of years, these features give Aquarius its enduring identity as the Water-Bearer.
The Age of Aquarius May Be Here — Unless You Ask an Astronomer
Aquarius has another famous association that comes from astrology rather than astronomy: the Age of Aquarius. Some astrologers believe this new age has already begun or is approaching, and the idea became especially famous during the counterculture of the 1960s. In one common astrological scheme, the precessional cycle is divided into 12 roughly equal ages of about 2,150 years each, with each age associated with one of the zodiac signs. The arrival of Aquarius has therefore been interpreted as the beginning of a new era for human society, often associated with ideas such as innovation, humanitarianism and social change.
The mechanism behind the idea, however, is a real astronomical phenomenon called precession. Earth’s rotational axis slowly changes direction, causing the position of the equinoxes to drift against the background stars over a cycle lasting roughly 26,000 years. Dividing that cycle into 12 gives astrological ages of a little over 2,000 years each, with the March equinox moving slowly from one part of the zodiac to the next.
Exactly when one age ends and another begins is disputed because astrological ages have no universally agreed boundaries. If instead we use the actual constellation boundaries recognized by astronomers, the March equinox is still in Pisces and won’t cross into Aquarius until around AD 2600. By that literal astronomical measure, the famous “dawning of the Age of Aquarius” hasn’t happened yet. You can read more about the difference between zodiac signs and real astronomical constellations in our guide to the zodiac constellations.
