Pisces—Latin for “fishes”—is a large but surprisingly faint constellation of the zodiac, traditionally representing two fish connected by long cords. It covers about 889 square degrees of sky, making it the 14th largest of the 88 constellations, yet it contains no truly bright stars. Even its brightest star, Alpherg, shines at only about magnitude 3.6. As a result, Pisces can be much harder to recognize than its considerable size might suggest.
Yet there is much more hidden among these faint stars than first appears. Pisces contains one of the finest spiral galaxies in the Messier catalog, a nearby dead star whose significance went unnoticed for almost a century, and a constellation tradition with roots reaching deep into antiquity. It also occupies a surprisingly important position in the modern astronomical sky: the Sun now lies within Pisces at the March equinox.
Use the Great Square to Find Pisces
From the Northern Hemisphere, Pisces is best seen during autumn, when it climbs into a favorable position during the evening. It can be seen from latitudes between roughly 90° north and 65° south, so it is visible from most inhabited parts of Earth. From northern mid-latitudes it reaches its highest point around November, although it can be observed over a much longer period on either side. The main difficulty isn’t its position in the sky but the faintness of its stars, so a dark, moonless location makes a considerable difference.
Fortunately, there is a much easier pattern nearby to guide you. Look for the Great Square of Pegasus, a huge four-star pattern high in the autumn sky. Don’t expect a small, compact square—the four stars surround an area considerably larger than your fist held at arm’s length. If you’re struggling to find it, locate the distinctive W-shaped Cassiopeia and Polaris, the North Star. Draw an imaginary line from Polaris through Caph, the star at the western end of Cassiopeia’s W, and continue in the same direction across the sky. This leads toward the Great Square of Pegasus.
Once you’ve found the Great Square, look below its southern side for the Circlet of Pisces, a small loop of faint stars forming the western fish. Don’t expect the Circlet itself to leap out from a brightly lit town or city. Its stars are mostly around fourth and fifth magnitude, so Pisces is much easier to trace away from strong light pollution. Once you’ve found the Circlet, however, the sprawling shape of the constellation becomes much easier to understand.
Pisces Traces a Large, Faint V Across the Sky
The Circlet represents the western of Pisces’s two fish. From there, a long line of faint stars extends away from it to form one of the traditional cords. The second fish lies on the other side of the Great Square of Pegasus, with another chain of stars running back from it. Seen as a whole, these lines give much of Pisces a broad V-shaped appearance.
The two cords come together at Alrescha (Alpha Piscium), near the point of the V. This simple geometry is much more useful for recognizing Pisces than trying to see two literal fish among the stars. The elaborate fish belong to traditional constellation artwork; in the actual sky, the Circlet, the long connecting lines and their meeting point provide the more useful pattern.
Even Pisces’s Brightest Star Is Faint
Alpherg (Eta Piscium) is the brightest star in Pisces, although at around magnitude 3.6 it is still relatively faint. That makes it a good illustration of just how inconspicuous Pisces is: the constellation covers more sky than most of the 88 constellations, yet doesn’t contain even a second-magnitude star.
Alpherg is an evolved yellow giant, meaning it has exhausted the hydrogen fuel that sustained it through the main part of its life and expanded beyond its earlier Sun-like stage. It lies roughly 350 light-years from Earth. Its designation also provides a small astronomical curiosity. Despite being Pisces’s brightest star, it carries the Greek letter Eta rather than Alpha.
Alrescha (Alpha Piscium) is fainter, but its position makes it one of the constellation’s most important stars. It lies where the two cords joining the fish come together, and its traditional Arabic name is associated with “the cord.” What appears as Alrescha is also not a single star but a multiple-star system.
The fact that Alrescha is Alpha Piscium while brighter Alpherg is Eta Piscium isn’t an error. The Greek letters assigned to stars in the Bayer system don’t always form a strict brightness ranking; position and other considerations could also influence their designation. In Pisces, Alrescha’s location at the junction of the two fish makes it far more prominent in the traditional figure than its brightness alone would suggest.
The Stars That Map Out the Two Fish
A number of other stars help trace Pisces’s large, faint outline:
- Alpherg (Eta Piscium) is the constellation’s brightest star, at about magnitude 3.6, and an evolved yellow giant roughly 350 light-years away.
- Gamma Piscium shines at about magnitude 3.7 and is the brightest star in the Circlet, making it particularly useful when identifying the western fish. The Circlet’s other principal stars include Theta, Iota and Lambda Piscium.
- Alrescha (Alpha Piscium) is a multiple-star system roughly 150 light-years from Earth.
- Omega Piscium is a roughly fourth-magnitude star toward the eastern part of the constellation.
- Iota Piscium is another fourth-magnitude star and forms part of the Circlet. At only around 45 light-years away, it is considerably closer to us than many of Pisces’s other prominent stars.
- Epsilon Piscium is another naked-eye star of roughly fourth magnitude lying along the constellation’s eastern reaches.
- Delta Piscium, at around magnitude 4.4, forms another part of the long stellar pattern traditionally used to trace the fish and their cords.
Pisces has no single bright star to anchor it the way Regulus does for Leo or Aldebaran does for Taurus. Instead, you have to build up the pattern gradually, tracing one faint star to the next across a surprisingly large stretch of sky.
Van Maanen’s Star: A Dead Star Feeding on Planetary Debris
One of the most remarkable stars in Pisces is far too faint to see with the unaided eye. Van Maanen’s Star is a white dwarf only about 14 light-years from Earth. A white dwarf is the small, dense remnant left behind after a star broadly similar to the Sun has exhausted its nuclear fuel and shed its outer layers.
Its real significance comes from an observation made more than a century ago. In 1917, astronomers recorded the spectrum of Van Maanen’s Star and found elements such as calcium in its atmosphere. That is unusual in a white dwarf because heavy elements should quickly sink out of sight beneath its surface. If they are still visible, something must be continually supplying them. Astronomers now know that the source can be rocky debris—the remains of asteroids or other small bodies from a former planetary system that are being torn apart and falling onto the star. In other words, evidence of material from another planetary system had been recorded in 1917, decades before astronomers discovered the first confirmed exoplanets. Nobody at the time knew what the clue meant.
M74 Offers a Face-On View of a Spiral Galaxy
Pisces contains one object in Charles Messier’s famous catalog: M74, a beautiful grand-design spiral galaxy roughly 32 million light-years away. Seen almost face-on from Earth, its sweeping symmetrical arms are filled with young blue stars, glowing regions of star formation and lanes of dark dust. NASA estimates that M74 contains around 100 billion stars, making it only somewhat smaller than our own Milky Way.
Yet M74 provides a good lesson in the difference between how impressive an object looks in a photograph and how easy it is to see through a telescope. Its enormous output of light is spread across a relatively large area of the sky, giving the galaxy low surface brightness. Instead of concentrating its light into a bright point, it appears through a small telescope as a faint, diffuse patch. NASA consequently describes M74 as one of the most difficult Messier objects to observe.
M74 is only the best-known of Pisces’s deep-sky objects. The constellation also contains interacting galaxies and much more distant galaxy systems, which we explore in our dedicated Deep-Sky Objects in Pisces guide.
One of Pisces’s Fish Was Once a Bird
Pisces has roots in ancient Mesopotamian astronomy, but the earliest figures in this part of the sky were not yet the two fish we recognize today. Babylonian astronomers associated these stars with separate figures, including a great Swallow and the goddess Anunitu. What is especially interesting is that some of the long connecting lines that would eventually become the cords of Pisces were already part of these much older star figures.
Over the centuries, the figures changed, but the idea of stars connected by long lines survived. Later Mesopotamian imagery even shows an intermediate stage in which a fish and a bird are joined by a V-shaped ribbon. Eventually the creatures changed too, producing the more familiar image of two fish connected by cords. By classical antiquity, the constellation had become recognizably similar to the Pisces shown on star charts today.
Greek tradition then gave the two fish a mythology of its own. Pisces became associated with Aphrodite and Eros and their escape from the monster Typhon. Versions of the story differ: in some they transform into fish to escape through the water, while in others fish carry them to safety. The Greek story therefore explains the pair in its own terms, but the connected figure in the sky had a much older history.
Why Pisces Is the First Constellation of the Zodiac
The zodiac forms a complete circle around the sky, tracing the Sun’s path through the stars over the course of a year. But a circle has no natural starting point, so astronomers needed to agree on one—a fixed “zero,” much like the zero-degree line of longitude used to measure position around Earth.
They picked the March equinox: the moment each year when the Sun, moving northward in our sky, crosses the celestial equator from the southern half of the sky into the northern half. That crossing point became the zodiac’s zero point. In the time of Hipparchus, during the second century BCE, it fell against the stars of Aries, near the constellation’s western end—which is why it’s still called the First Point of Aries today.
But Earth slowly wobbles on its axis in a roughly 26,000-year cycle called precession. As a result, the equinox point gradually drifts against the background stars—not because the Sun’s annual path has changed, but because Earth’s wobble slowly changes which stars lie behind that point in the sky.
More than two thousand years later, that drift has carried the March equinox out of Aries and into Pisces. The old name never caught up: one of astronomy’s most important reference points is still called the First Point of Aries, even though it now lies in Pisces. For this reason, Pisces is sometimes described as the “first constellation of the zodiac”—not because the constellations have an official first member, but because Pisces now contains the zodiac’s traditional starting point.
