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 spring 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

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