All About The Pisces Constellation

Pisces is sometimes an overlooked constellation, owing to its less exciting visual shape and associated imagery. Seen as two fish tied at the tail by a cord, Pisces can struggle to capture the imagination in the same manner as more fearsome constellations like Taurus and Leo. Despite a more modest appearance, this constellation holds a place of some prominence in the night sky. Sometimes known as the first constellation of the Zodiac, Pisces is a constellation whose importance should not be underestimated.

Pisces - A Symbol of Change

Pisces constellation plays an important role as the backdrop to the March equinox, an important solar and cultural event. This is one of two times in a year when the Sun’s center is directly over the equator, the other being the September equinox. An important event, you might know the March equinox by a different name. In the northern-hemisphere, it is referred to as the Vernal or Spring equinox. In the southern- hemisphere, it goes by the Autumnal or Fall equinox. The September equinox actually goes by the same names, but it is the opposite in each hemisphere.

During the March equinox, the Sun appears in the region of the sky dominated by Pisces. Not only does the equinox symbolize the position of the Sun, this moment also marks the completion of one Tropical year, meaning the Earth has completed one full rotation around the Sun.

While this statement may seem odd, considering the new year is traditionally celebrated at the end of December in the Western world, a Tropical year is a particular means of measuring the Earth’s rotation around the Sun. While a traditional year of the Gregorian calendar (our current calendar) is measured as a strict 365.2425 days (the decimal point being accounted for with each leap year) the Tropical year measures the actual time it takes for a full rotation, meaning every Tropical year is a different length depending on variation in the Earth rotation.

Given the significance of Pisces’ place in the background of the March equinox and each tropical year, it has earned its title as the first constellation in the Zodiac.

By Till Credner - Own work: AlltheSky.com

A Constellation Ages Old

Like many of the constellations covered previously, Pisces is one of the original forty-eight constellations covered by the Greek-Egyptian astronomer Ptolemy in the second century. While the name we know it by comes from the Latin word for ‘the fish’ (plural), the constellation has been known by this description from civilizations predating the Romans. Babylonian astronomers recognized a pair of fish in the sky, labeling the constellation as DU.NU.NU, which translates roughly to ‘the fish cord or ribbon.’ The existence of a cord binding the fish together at the tail, seems to suggest some continuity between the Babylonian and Greek traditions of Astronomy.

In Greek and Roman tradition, Pisces is meant to symbolize Aphrodite and her son Eros (Venus and Cupid in the Roman tradition), who were forced to turn into fish and jump into the Euphrates river, in order to escape the monster Typhon who had been sent by Gaia to defeat the gods of Olympia.

It is said that the two tied themselves together, so as not to lose one another in the raging river. In some Roman versions of the myth, Venus and Cupid rode on the backs of fish to escape, rather than becoming fish themselves.

Notable Stars of Pisces Constellation

Pisces is comprised of nine named stars. The brightest star in the constellation is officially named Eta Piscium, but it goes by the unofficial name Kullat Nunu, Babylonian words translating to fish (Nunu) and bucket or cord (Kullat). This name is a unique case, as most stars are known by a Greek, Latin, or Arabic name. Like many stars in the night sky, this point of light we see as Eta Piscium is actually a binary pair, meaning two stars are orbiting around each other. The larger of these is Eta Piscium A, which is twenty- six times larger than our Sun, and three-hundred-sixteen times more luminous.

Though not the brightest, the star Alpha Piscium is likely the most famous of this constellation. Its traditional name is Alrescha, a derivation of the Arabic word al-rishā’ meaning ‘the cord.’ This star holds a particular place in the constellation, forming the central point where the two fish meet, a location which earns it its namesake. Alrescha is another binary star system.

Perhaps the most interesting star of Pisces is van Maanen's Star (Van Maneen 2). Dim enough that it cannot be seen with the naked eye, van Maanen's Star is a white dwarf, one of the most difficult stars in the galaxy to locate, due to their small size and limited luminosity. Still, what makes this star so unique is its closeness to our solar system. At 14.1 lightyears from our Sun, van Maanen's Star is the closest solitary white dwarf to us, and the third closest of its type.

Wonders of the Deep Sky

The most notable deep-sky object of the Pisces constellation is Messier 74, the ‘Phantom Galaxy’. Located thirty-two-million light years from Earth, this galaxy contains two well defined spiral arms, making it an archetype example of a grand design spiral galaxy. M74 is a bit of an oddity for those seeking to view it. For amateur astronomers, the ‘Phantom Galaxy’ is incredibly dim and difficult to find, typically requiring a location with minimal light pollution to view. For professional astronomers, M74 represents a spiral galaxy ideal for study.

With the right tools, the galaxy’s ‘face-on’ orientation and apparent size make it an ideal candidate for study, as do its well-defined characteristics. This galaxy is also rich in observable phenomena, containing roughly one-hundred-billion stars; three supernovae have already been observed in the past 20 years.

In 2005, an ultra-luminous x-ray source was discovered in M74, an object which was putting out more x- rays than a neutron star. The source is believed to be an intermediate-mass black hole, a classification that is both rare and still poorly understood.

Hunting the Dim

Much like Messier 74, Pisces is surprisingly dim despite its large size (the 14th largest constellation). Still, there are several tricks to locating the constellation without too much difficulty. For those in the northern-hemisphere, it is best observed in early Autumn, particularly in the first weeks of November.

Surrounding constellations are Andromeda, Pegasus, and Aries—a crowded neighborhood, but luckily there is a trick to locating it. By identifying the body of the constellation Pegasus (seen as a large square), an observer can find the head of the eastern fish directly below. From there, it is easy for any sky-watcher to trace out the rest of Pisces, and take in this notable section of the night sky.