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Glossary term: Pisces

Description: Pisces is a constellation in the Zodiac, i.e. the stars that make up this constellation are in the part of the sky that intersects with the ecliptic – with the plane defined by the Earth's orbit around the Sun. Hence, from our point of view here on Earth, we can regularly find the Sun, and also the other planets in the Solar System, in this constellation. In the case of the Sun this is from around mid-March to mid-April, which includes the time of the March equinox. (Of course if the Sun is there, we cannot see the constellation's stars.) Pisces is one of the 88 modern constellations defined by the International Astronomical Union, but it goes back much further – it was already one of the 48 constellations named by the 2nd century astronomer Claudius Ptolemy.

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Term and definition status: This term and its definition have been approved by a research astronomer and a teacher

The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".

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In front of the curve of the Milky Way we find the hourglass-shaped Orion and the bright Pleiades star cluster.

Warm Winter Night Over Spiš Region

Caption: Winner in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.   This image, taken in Slovakia in January 2022, shows regions of the Milky Way and a rich variety of constellations. The summer constellations of the northern hemisphere are very low in the sky towards the bottom-right. The bright stars of Cygnus and Lyra shine through the artificial lights at the horizon. The huge array of northern winter and autumn constellations with many bright stars are associated with diverse cultural stories. For the Lakota people in North America the belt of the Orion constellation represents the spine of a bison (“Tayamnicankh”). Orion, the Hunter of Greek mythology, is sometimes described chasing the Seven Sisters, the Pleiades. The Arabs transformed this view by considering the follower of the Pleiades only one star instead of a constellation. Aldebaran, the star in the right eye of Taurus, the Bull, comes from this interpretation, because the name Aldebaran derives from al-dabaran, The Follower. At the bottom-right, on the horizon, we can see the milky lightcone of the Zodiacal light stretching from the constellation Pisces through Aries, almost reaching the Pleiades, indicating the path of the planets and the Moon in this area. The Pleiades and the Hyades together form a gate on this path, where the heavenly bodies occasionally pass before entering the Milky Way. The planets were considered sheep in ancient Babylon and the modern constellation Orion was considered the “True Shepherd” of the Sky, with his shepherd’s tool reaching the ecliptic. In Roman tradition, the bright white star above the Pleiades and the Milky Way is called Capella, the Goat, which can be traced back to an Egyptian constellation in this area. Above the treetop in the middle-right part of the image, we see the autumn square, the Andromeda Galaxy and the W-shaped pattern of Cassiopeia. To the left of this group, in the central part of the visible Milky Way, is the constellation Perseus, with Cepheus in the dark area above Cassiopeia completing the celestial family. The Andromeda saga is a Greek story from the area that is now called Israel, and is rooted in Syrian traditions. The location of Andromeda was considered by the ancient Babylonians as the location of the goddess of sexual love, and by the Syrians as the location of the goddess of fertility. According to the saga, Andromeda was chained to a rock at the coast of Jaffa (Tel Aviv) in order to protect her land from a sea monster. The name of the hero who rescued her is Perseus, probably meaning “from Persia” (today’s Iran). Noticeable in the valley are the lights from towns. The yellow light above the horizon indicates larger cities there, which are given away by their light pollution.
Credit: Robert Barsa/IAU OAE

License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons

Related Diagrams

Aquarius Constellation Map

Caption: The constellation Aquarius along with its bright stars and surrounding constellations. Aquarius is surrounded by (going clockwise from the top) Pegasus, Equuleus, Aquila, Capricornus, Piscis Austrinus, Sculptor, Cetus and Pisces. Aquarius lies on the ecliptic (shown here as a blue line), this is the path the Sun appears to take across the sky over the course of a year. The Sun is in Aquarius from mid February to mid March. The other planets of the Solar System can often be found in Aquarius. Aquarius spans the celestial equator and is thus visible at some time in the year from all of planet Earth. In the most arctic or antarctic regions of the world, some parts of the constellation may not be visible. Aquarius is most visible in the evenings in the northern hemisphere autumn and southern hemisphere spring. The yellow circles with plus symbols superimposed on them mark the globular clusters M2 and M72. The green circles superimposed on plus symbols mark the planetary nebulae NGC 7293 (the Helix Nebula) and NGC 7002 (the Saturn Nebula). M73 (marked with an x symbol) is a coincident grouping of stars previously erroneously classified as an open cluster. The y-axis of this diagram is in degrees of declination and with north as up and the x-axis is in hours of right ascension with east to the left. The sizes of the stars marked here relate to the star's apparent magnitude, a measure of its apparent brightness. The larger dots represent brighter stars. The Greek letters mark the brightest stars in the constellation. These are ranked by brightness with the brightest star being labeled alpha, the second brightest beta, etc., although this ordering is not always followed exactly. The dotted boundary lines mark the IAU's boundaries of the constellations and the solid green lines mark one of the common forms used to represent the figures of the constellations. Neither the constellation boundaries, nor the lines joining the stars appear on the sky.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons


Pisces appears as a SW-pointing v-shape with loops at the end of each line. The ecliptic runs WSW to ENE through Pisces.

Pisces Constellation Map

Caption: The constellation Pisces along with its bright stars and surrounding constellations. Pisces is surrounded by (going clockwise from the top) Andromeda, Pegasus, Aquarius, Cetus, Aries and Triangulum. Pisces lies on the ecliptic (shown here as a blue line), this is the path the Sun appears to take across the sky over the course of a year. The Sun is in Pisces from mid March to mid April. Thus the Sun is in Pisces at the March equinox. At this point the ecliptic crosses the celestial equator. The Sun’s location at the spring equinox is used to set the zero point of the Right Ascension positional coordinate. The other planets of the Solar System can often be found in Pisces. Pisces spans the celestial equator and is thus visible at some time in the year from all of planet Earth. In the most arctic or antarctic regions of the world, some parts of the constellation may not be visible. Pisces is most visible in the evenings in the northern hemisphere autumn and southern hemisphere spring The grand design spiral galaxy M74 is marked on this diagram with a small red circle. The y-axis of this diagram is in degrees of declination and with north as up and the x-axis is in hours of right ascension with east to the left. The sizes of the stars marked here relate to the star's apparent magnitude, a measure of its apparent brightness. The larger dots represent brighter stars. The Greek letters mark the brightest stars in the constellation. These are ranked by brightness with the brightest star being labeled alpha, the second brightest beta, etc., although this ordering is not always followed exactly. The dotted boundary lines mark the IAU's boundaries of the constellations and the solid green lines mark one of the common forms used to represent the figures of the constellations. Neither the constellation boundaries, nor the lines joining the stars appear on the sky.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons


Aries is mostly stars with only a few bright stars in the constellation’s north joined by a curved line. The ecliptic runs WSW to ENE

Aries Constellation Map

Caption: The constellation Aries along with its bright stars and surrounding constellations. Aries is surrounded by (going clockwise from the top) Triangulum, Pisces, Cetus, Taurus and Perseus. Aries lies on the ecliptic (shown here as a blue line), this is the path the Sun appears to take across the sky over the course of a year. The Sun is in Aries from mid April to mid May. The other planets of the Solar System can often be found in Aries. Aries lies just north of the celestial equator and is thus visible at some time in the year from all of planet Earth except for the most antarctic regions of the world. Aries is most visible in the evenings in the northern hemisphere winter and southern hemisphere summer. The y-axis of this diagram is in degrees of declination and with north as up and the x-axis is in hours of right ascension with east to the left. The sizes of the stars marked here relate to the star's apparent magnitude, a measure of its apparent brightness. The larger dots represent brighter stars. The Greek letters mark the brightest stars in the constellation. These are ranked by brightness with the brightest star being labeled alpha, the second brightest beta, etc., although this ordering is not always followed exactly. The dotted boundary lines mark the IAU's boundaries of the constellations and the solid green lines mark one of the common forms used to represent the figures of the constellations. Neither the constellation boundaries, nor the lines joining the stars appear on the sky.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons