Aquarius is a constellation in the Southern Hemisphere and one of the oldest documented constellations of the Zodiac. There are no particularly bright stars in the constellation and it can be difficult to view with the naked eye. However, it is large — spread out over 980 square degrees and the 10th largest constellation in the sky.
As is the case with all of the Zodiac constellations, Aquarius was recorded in the second century by the Greek astronomer Ptolemy. Its name means "cup bearer" or "water bearer" in Latin.
The constellation can be seen in the spring in the Southern Hemisphere and the fall in the Northern Hemisphere.
- Right Ascension: 22.71 hours
- Declination: -10.19 degrees
- Visible: Between 65 degrees and -90 degrees
- Best viewed: During October at 9 p.m.
Aquarius is located near Cetus (the whale), Pisces (the fish), Delphinus (the dolphin), Eridanus (the river), which are all part of what is often referred to as the water or sea section of the sky where there are a cluster of water-related constellations.
Notable stars and objects
The brightest star in the Aquarius constellation is a rare yellow supergiant known as beta Aquarii, also known as Sadalsuud. It is 600 light-years away and has a magnitude of 2.9, which is low.
Alpha Aquarii, or Sadalmelik, is a giant star located 760 light-years from Earth and has a magnitude of 2.95.
Located 158 light-years from earth, Gamma Aquarii, or Sadachbia, has a magnitude 3.8.
Zeta Aquarii is at the center of the Y-shaped configuration that forms Aquarius’ water jar. The other stars in the asterism forming the jar are Gamma, Pi and Eta Aquarii. The stream of water consists of more than 20 stars, ending with Fomalhaut.
Aquarius includes a number of planetary nebulae, including NGC 7009, one of the brightest in the sky. It also known as the Saturn Nebula because it has a ring that resembles Saturn and was first observed in 1782 by Sir William Herschel, a German-born British astronomer.
Aquarius also boasts the closest of all planetary nebulae — NGC 7293, or the Helix Nebula — which is just 400 light-years from Earth.
The Greeks linked this constellation with Ganymede, the cup bearer to the gods. According to lore, Ganymede was a good-looking young man who was the object of Zeus' affection and was brought to Mount Olympus, where he served as cup bearer to the gods and was granted eternal youth.
Aquarius has also has various meanings and associations in other cultures.
Babylonian astronomers identified the constellation as representing the god Ea, or "The Great One," which was often pictured with an overflowing vessel. In ancient Egypt, the water bearer’s jar was said to cause the spring overflow of the Nile when it was dipped into the river. The Chinese astronomers viewed the "stream" as soldiers.
In astrology, which is not a science, Aquarius is the 11th sign in the Zodiac and represents those born between Jan. 20 and Feb. 18.
— Kim Ann Zimmermann, SPACE.com contributor