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Glossary term: Constellation

Description: A constellation in modern technical terms is a polygonal segment of the celestial sphere. The International Astronomical Union has divided the entire celestial sphere into 88 regions – constellations. This is based on those used in Ancient Greece together with more recent additions, especially in the southern hemisphere. Each of the 88 constellations occupies a certain part of the sky, and therefore, each of the heavenly bodies, from stars to galaxies to nebulae, etc., can be associated with a constellation. The Zodiac are 13 constellations that overlap the ecliptic (the annual path traced by the Sun across the celestial sphere). The 13 constellations are: Ophiuchus, Sagittarius, Capricornus, Aquarius, Pisces, Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, and Scorpius.

Constellations contain grouping of stars (asterisms) suggesting a pattern as seen from Earth. These patterns are imaginatively described as representing humans, animals, or other recognizable objects.

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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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The bright streak of a meteor is reflected in a body of water. The Large Magellenic Cloud is in the top left as a fuzzy line

Between Two Skies

Caption: Honourable mention in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.   Taken from Narrabri, Australia, in April 2014, this photograph shows a meteor next to the Large Magellanic Cloud and the reflection of all this in the water. The Magellanic Clouds are named after the Portuguese explorer Ferdinand Magellan, who made the first maps of the southern part of South America in the early 16th century but did not survive his expedition voyage. His shipmates called the two nebulae after him, and it was only in the 20th century that astronomy research discovered that they are in fact dwarf galaxies accompanying our own. In the 18th century, the French mathematician J-N. Lacaille, who lived in South Africa for some years in order to draw maps of the sky and the land, invented some new constellations. He measured the positions of some faint stars and listed them in his star catalogue, but did not try to overlay beautiful drawings of real-world objects on the star patterns, so he could name them however he wanted. He was based in the trade station that is now the city of Cape Town and, from this bay, Table Mountain is visible. Lacaille learned from the navigators that they used the clouds around this mountain to predict whether or not the wind would blow in the correct direction and allow for sailing. Normally, there is a huge white cloud at the top of Table Mountain, so Lacaille considered the larger one of the two dwarf galaxies not a “Magellanic Cloud”, but the cloud at Table Mountain. Consequently, he invented the constellation “Mensa”, Table Mountain, in the small area of faint stars directly attached to this dwarf galaxy.
Credit: Fabrizio Melandri/IAU OAE

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In a field of countless stars dotted by clouds and reflected in water, the three stars of Orion’s belt poke above the horizon

Constellations from the World

Caption: Third place in the 2022 IAU OAE Astrophotography Contest, category Time lapses of celestial patterns.   This video tries to cover a huge variety of phenomena in the night sky from different locations — Iceland and China — and is designed like a theatre play, starring mother nature herself. It starts with a blue twilight sky that dims and unveils the starry night sky on the stage with terrestrial clouds on a beautiful landscape. The impressive parts of the southern Milky Way between Scorpius and Crux, with the pointer stars Alpha and Beta Centaurus, are shown passing by majestically. The terrestrial clouds blur the stars and allow us to recognise their colours even more clearly. The first act presents the starry sky in human culture. One scene shows the Pleiades rising over the top of a hill, while a human moves hastily with a flashlight below. At the very moment that the Pleiades rises behind the hill, the beam of the flashlight hits the camera. There is some humour in this remarkable scene referencing the human relationship to the rise of the Pleiades in cultural history. The next scene shows The Big Dipper, Ursa Major, as a typical northern constellation, with an arch of aurora below it. The aurora evolves and moves but does not change much fundamentally. In northern human cultures, aurorae were often interpreted as the ghosts of ancestors, but this play does not spend any time on human beliefs, instead moving the view southwards in the subsequent scenes. First we see some stars rising shortly before sunrise. The lightcone of Zodiacal light appears in Gemini/Taurus and the horizon gets brighter. In the next scene, at about 1 minute and 13 seconds, we see Orion setting over water, so that the water surface mirrors the celestial scene. Some clouds crossing the image prove that the videos were really taken on our beautiful planet, and, since Orion’s shoulder and foot are seen to set almost simultaneously, this sequence must have been captured almost at the equator. In this area, the bright stars of Orion look like a huge butterfly, with Orion’s Belt forming the body, and the quadrilateral of four bright stars interpreted as the wings. As in a real theatre, we now see a curtain before the next act of the heavenly play, an aurora curtain. The next act presents several bright stars in original scenes: the Chinese asterisms of The Tail (of the Azure Dragon), the Winnowing Basket and the Southern Dipper, which are seen in the modern constellations Scorpius and Sagittarius. The striking shape of Corona Borealis that has been recognised as an asterism in many cultures all over the globe, is also shown, as are some planets, the stars Vega and Deneb with adjacent areas, Altair, the Milky Way, and the characteristic W shape of Cassiopeia that has also been an asterism for many cultures on Earth. The outro presents two more scenes with a smooth and silent night sky.
Credit: Stephanie Ye Ziyi/IAU OAE

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Over a cluster of small telescope domes the Milky Way juts upward from the horizon. Two fuzzy blobs are on the right

Chilean Nights

Caption: Honourable mention in the 2022 IAU OAE Astrophotography Contest, category Time lapses of celestial patterns.   Shot in December 2020, this time-lapse shows the sky from San Pedro de Atacama, Chile, in the southern hemisphere. Right in the first frame we can see our home galaxy, the Milky Way, as well as both the Large and Small Magellanic clouds, two satellite galaxies orbiting the Milky Way. In the bottom of the image the bright stars Rigil Kentaurus and Hadar (also known as Alpha and Beta Centauri) are visible, both in the constellation Centaurus. Just above, we can also see the small constellation Crux, visible from the northern tropical circles southwards. It is important for navigation purposes because its longer axis indicates the direction of the celestial south pole. The bright whitish star in the top of the image and to the right of the Galaxy is Canopus, one of the brightest stars in the night sky, located in the constellation Carina. Canopus is the second brightest star in the sky, while Rigil Kentaurus is the third brightest. In some of the next frames, Orion, the great hunter, appears clearly with its bright stars and its characteristic asterism, the belt, composed of three aligned bright stars. Since this video was taken from the southern hemisphere, the Greek hero from the northern hemisphere seems to be performing a headstand. We can also see the planets Jupiter and Saturn in a close conjunction, even finding themselves in the significant beam of Zodiacal light setting down below the horizon. There are also a few meteors blinking in some of the frames, one of them with a long-lasting and developing trail. The very bright object rising from behind the volcanoes of the Andes, creating spectacular shadows and crepuscular rays, is the Moon. In the last frame we see the Moon next to Saturn and Jupiter.
Credit: Robert Barsa/IAU OAE

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Above a volcano, a bow-tie-shaped Orion is peppered with bright sweeps of nebular gas

Orion Rises Over Mount Etna

Caption: Honourable mention in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.   Taken in February 2021, this image is a composite of an astronomy picture in the background and Mount Etna, the famous volcano in Sicily, Italy, in the foreground. Prominently, we see the red hydrogen clouds in space in the area of Orion. Barnard’s Loop is the gigantic bow with the Great Orion Nebula and the Horsehead Nebula in its centre. The deeper-coloured Horse Head is below the southernmost stars in Orion’s Belt, which is the line of white stars above the red nebula. Clearly visible is also the division between the Small and the Great Orion Nebula, the circular and the trapezium-shaped structure in light pink within which one of the nearest star-forming regions is located. The nebula is only a bit more than a thousand light-years away. In the middle-left, close to the edge of the image, the small red structure is the Monkey Head Nebula still in the constellation Orion. It hosts a young star cluster and the deep red colour of this hydrogen cloud indicates its potential to build new stars in the future if the material is compressed again. All these reddish objects are strongly processed in this image, as they are not visible to the unaided eye. Still, this image provides an interesting feature; the red supergiant star Betelgeuse lies in the middle of the image and it seems to be directly above the active volcano Mount Etna. At the foot of this volcano is an ancient settlement, the city of Catania. We consider both Betelgeuse and Mount Etna somehow dangerous — but which of them will erupt first? Ok, we know that Etna occasionally erupts. Normally it exhibits only small eruptions, but the bigger ones happen every few centuries. We also know that Betelgeuse as a giant star will become a supernova in the future. Astronomers call the timescale for the potential supernova short, implying that it will be only 10 000 or maybe 100 000 years until this star explodes. This is “soon” for astronomers, meaning that on Earth, two to four precession cycles will pass by (with the consequence that the Sahara will turn green and dry again two to four times), continental drift will take Africa further north and cause the Alps to grow in height, the Niagara falls in America will wash the rock completely away and only after all this (and much more) happening on Earth will Betelgeuse explode as a supernova. Mount Etna is much more dangerous for the people in Sicily, and Catania in particular, because it will erupt sooner.
Credit: Dario Giannobile/IAU OAE

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A dark sky over a dry desert landscape. The brightest star in the image is rising on the lower left

The Culmination of Canopus

Caption: Honourable mention in the 2022 IAU OAE Astrophotography Contest, category Time lapses of celestial patterns.   This time-lapse video was shot in January 2018 from the Joshua Tree National Park, USA, and follows the path of Canopus, the second-brightest star in the night sky, as it moves from left to right, almost touching the horizon. The landscape is illuminated by the Moon.  Canopus is associated with the rudder of the ancient Argo constellation, the Ship, nowadays split into the three modern constellations Vela, Puppis and Carina, the last of which contains Canopus. Owing to its brightness, Canopus has caught the attention of several cultures around the world throughout history. For instance, the Navajo people of North America named the star as the Coyote, and say that the coyote took part in the creation of the Universe. The Kalapalo people of Brazil associated Canopus with a duck, with other bright stars making up the body parts of the animal. The appearance of Canopus in the sky indicates the coming of the rainy season.
Credit: Fabrizio Melandri/IAU OAE

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The bow tie shaped Orion over dry, rocky outcrops. Sirius appears as a bright star between two pillars of rock

Winter Constellations

Caption: Second place in the 2022 IAU OAE Astrophotography Contest, category Time lapses of celestial patterns.   Sirius, the brightest star in the night sky, is shown rising, setting and passing by. Sometimes constellations and asterisms are also visible, including Orion, Taurus and the Pleiades. In the first scene, the aforementioned constellations are covered by a semi-transparent golden veil. The next scenes show it rising in a dark blue night sky. In one of the scenes, a planet brightly decorates the faint constellation Pisces. The videos were taken above various landscapes and places of cultural heritage on Earth. Some of them simply show monuments in the desert, while others show palm trees with waving leaves.
Credit: Amirreza Kamkar/IAU OAE

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The Southern Cross forms a kite shape in front of the mottled light and dark patches of the Milky Way.

Cen-Lup-Cru-Panorama: Centaurus Carrying the Beast and Riding Along the Milky Way

Caption: Winner in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.   This image was taken in February 2020 in the Coquimbo Region along the northern coast of Chile. It is one of the best places on Earth for astronomical observations, thanks to its clear skies, lack of light pollution and lack of precipitation, as it is close to the Atacama desert, one of the driest places on our planet. It is no coincidence that many of the most modern professional observatories are located here. The picture shows prominent patterns visible in the southern latitudes, containing rich cultural significance for various Indigenous groups of the southern world. In the bottom of the image towards the right, the Southern Cross is prominent. The orange star at the top of the Southern Cross is called Gacrux (gamma crux). The people in Chile celebrate the beginning of winter at the beginning of May when the constellation Crux is high up in the sky; for them it is a symbol of the start of the cold season. For the festival of the Cruz de Mayo (the Great Cross), they put candles next to crosses in their villages when the constellation Crux is high. As in Christianity, the four endpoints (stars) of the cross symbolise the cardinal virtues. For some indigenous Chileans, they represent the fundamental cultural principles: force, reciprocity, wisdom, and spirituality. Unlike modern constellations that are arrangements of several stars, Indigenous peoples sometimes associate stories with individual stars. In the case of the Southern Cross for example, the Boorong, Djab Wurrung and Jardwadjali peoples of Australia refer to the star Gacrux as Bunya (the ring-tailed possum). From the Southern Cross to the left of the image are two bright stars, these are called the pointer stars (as they point to the Southern Cross). The Djab Wurrung and Jardwadjali people refer to the pointer stars as the Bram-bram-bult brothers, who hunted and killed the giant Emu Tchingal. Alpha Centauri, which is the brighter and whiter of the two pointer stars, is the closest star to the Sun that we can see with our eyes, located just over four light-years away. To the bottom left of the Southern Cross is a dark nebula, which the Indigenous Australians see as the head of the Emu Tchnigal (the Coalsack Nebula). The pointers are located on the neck of the Emu. The image also shows two other IAU constellations, Centaurus (The Centaur) and Lupus (The Wolf), and HII regions of the Eta Carina Nebula (seen in pink).
Credit: Uwe Reichert/IAU OAE

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The Milky Way arches over an African grassland. Its diffuse glow is interrupted by a stream of dark patches.

Milky Way Arch over Amboseli National Park

Caption: Winner in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.   This image was taken in July 2016 from the Amboseli National Park in Kenya, located close to the equator. In Egyptian mythology from northern Africa, the Milky Way was associated with a river sailed by gods and souls. The Zulu in South Africa interpret this pattern of dark and bright clouds of stars as an animal with black and white skin, whereas the South African Khoikhoi and San considered it “The Star’s Road”. In several South African cultures, the arch of the Milky Way is a pathway to the heavens formed by a mother goddess, according to a South African creation myth that was adopted in the 19th century from early ethnological research, but has vanished today. In the middle-right of the image we find the bright red star Antares in the modern constellation of the Scorpion and at the upper-left edge is the white star Vega that is considered a Male Steenbok by the peoples around Cape Town. Indigenous Australians have many names for the Milky Way. The Yolnu people of Arnhem Land in Australia’s Northern Territory refer to the Milky Way as Milnguya, the sky river. One of the prominent patterns in this image is associated with the contrast between the light and dark regions of the Milky Way. These dark regions are cool dense clouds of interstellar dust and gas, which block the light from stars behind them. One of the prominent patterns is that of the Celestial Emu referred to as Tchingal by several Indigenous peoples of south Australia. The head and beak of the emu (the Coalsack Nebula) lie to the bottom-left of the Southern Cross (seen in the far bottom-right of the image), and the body and legs stretch leftward from it. Other indigenous groups associate the dark regions with caves or waterways. The orientation of the emu over the year provides important clues as to when it is time to pick emu eggs, and when the eggs are hatching. In some months, when these clouds of the Milky Way are close to the horizon, they are not considered as emu at all but as two creeping crocodiles. The modern figure of the dark Pipe Nebula is clearly visible above the centre of the Galaxy; the smoke of this pipe reaches the colourful rho Ophiuchi region next to Antares in Scorpius, the orange-red star just above the Milky Way. Antares is referred to by the Boorong people as Djuit, the red-rumped parrot, while the Kokatha people of the Western Desert refer to Antares as Kogolongo, the red-tailed black cockatoo. In addition, some notable constellations can be seen: Cygnus, Aquila, Lyra, Scorpius, Sagittarius, Crux, and Centaurus. The pointer stars, Alpha and Beta Centauri, are occasionally interpreted as The Eyes of the Beast in some South African traditions.
Credit: Amirreza Kamkar/IAU OAE

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The curve of the Milky Way over a road. Bottom left, two bright stars form a line pointing to a kite-shaped stellar assembly

Most Brightest Stars of the Sky

Caption: Honourable mention in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.   Taken in March 2016 in Bromo-Tengger-Semeru National Park, Java Island, Indonesia, this image shows the arch of the Milky Way and many prominent constellations, including many of the brightest stars in the night sky. In the lower-left corner, we see Rigil Kentaurus and Hadar, the first one lower and the other higher up, both located in the large constellation Centaurus. As pointers they point towards Crux, the Southern Cross, whose long axis points towards the southern pole, which is located roughly at the horizon because the Island of Java is almost at the equator. Crux is almost entirely obscured by clouds, with only the four bright stars visible in the photograph. Confusingly, the asterism of the False Cross (consisting of stars in Argo, The Ship) is clearly prominent a bit further up the Milky Way. The pinkish spot between the true and the False Cross is the Carina Nebula, located about 8500 light-years from Earth, in the constellation Carina, and invisible to the unaided eye. In Carina we can also find Canopus, the second-brightest star in the night sky, seen just below the Galaxy and above the road on the ground. Even brighter is Sirius, the brightest star in the night sky. Sirius lies in the constellation Canis Major, The Great Dog, one of the dogs that follow Orion, the Hunter, who is depicted in the right half of this image, just above the clouds at the horizon. Orion’s Belt of three bright stars points to Sirius in the upper left and to Aldebaran in the lower right, just above the horizon. Orion contains some of the brightest stars in the sky, making it the most colourful constellation as it hosts Rigel, the bright bluish star below the Galaxy toward the right, and Betelgeuse, the reddish bright star higher up and to the right of Rigel. Between them we find the three stars that comprise the belt of Orion, a famous asterism. Just next to the belt we find the Great Orion Nebula, a star-forming region whose bright centre is visible to the unaided eye and also in this image. Above Betelgeuse but on the opposite side of the Galaxy, we see the bright star Procyon, whose name means literally “Before the Dog”. It is mythologically often considered a tiny one-star dog asterism accompanying Orion, and transformed into the modern constellation of Canis Minor. In the upper-right corner, the Beehive Star Cluster in the constellation Cancer is easily recognisable. Below it, we find the constellation Gemini with the stars Pollux and Castor, which are not prominent in this image. In contrast, the bright white star Capella in the constellation Auriga, the Charioteer, shines through the clouds at the middle-right edge of the image. Some light pollution is visible along the road.
Credit: Giorgia Hofer/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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Above a flat, cracked landscape, Orion is shaped like a bow tie. Just above the horizon is a diffuse cluster of bright stars.

Luminous Salar de Uyuni

Caption: Winner in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.   This black and white image taken in February 2017 in Uyuni Salt Flat of southwest Bolivia, the biggest salt flat in the world, shows one of the most recognisable constellations, Orion the hunter, and the open star cluster of the Hyades directly above the clouds at the horizon. Various cultures have different stories associated with Orion. The Aymara in this area of the world (Bolivia and Northern Chile) consider Orion’s Belt to be a Sky Bridge (chacka cilitu) or a Stairway made out of dough. This stairway is rather obvious in this picture. It appears as if the stars in the sky are scattered like grains of salt on the ground — an amazing composition. For the Aymara, who were Christianised by the Spanish conquistadores, Orion and the Stairway are connected to the November festivals of the dead ancestors and the souls. In contrast to the original Christian culture, for these people in the southern hemisphere these festivals mark the beginning of summer, not the beginning of winter. While in the north, the “ghosts” of the ancestors are represented by the foggy weather in November, the Aymara greet the ancestors with flowers. This photograph in the dry salt flat, in contrast, seems to show the unlivable loneliness where the photographer meets the souls of the deceased. The Yolnu people of Arnhem Land in Australia’s Northern Territory have a rich culturally significant story associated with Orion that carries a lesson. It tells of the three brothers of the Kingfish clan and their canoe Djulpan. Owing to their lack of patience, the brothers ate the sacred Kingfish, angering the Sun woman Walu who created a waterspout that sent them into the sky. Looking at the constellation Orion, the three stars in Orion’s belt represent the three brothers, Orion’s sword is the fishing line, and the two dimmer stars Bellatrix and Saiph form the two ends of the canoe Djulpan.
Credit: Stephanie Ye Ziyi/IAU OAE

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Through tree branches we see the hourglass shape of Orion.

The Hunter in the Forest

Caption: Honourable mention in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.   Taken in December 2016, this image shows a clear and starry sky over the Masaya Volcano National Park in Nicaragua. The constellation Orion is the most prominent pattern in this image. Orion is associated with a great hunter according to Greek culture, and is seen here right in the middle. The reddish star in the centre is Betelgeuse, the second-brightest in this constellation and one of the brightest in the night sky. Above and to the right of Betelgeuse we find Bellatrix, another bright star, forming the right shoulder of the hunter. Extending a line from Bellatrix to the right, we find a crookedly aligned group of faint stars comprising Orion’s bow. We can also easily see a group of three aligned bright stars forming the belt of the hunter, an asterism recognised by many different cultures. Just below his belt we can see the silverish glittering that was interpreted as the metal of Orion’s sword or knife by the Greco-Roman tradition. It was alternatively interpreted as a fish roasted on a campfire by some cultures in Australia. In its centre, with binoculars we can see the Small and the Great Orion Nebula, together forming a giant cloud of dust and gas where new stars are being formed. To the lower-left of the silverish compound of tiny stars and nebulae, there is a bright star called Saiph, the Arabic term for “Sword” or “Sabre” because it was considered the tip of a huge knife with a curved upper part. To the right of this, there is the bright bluish star Rigel, an Arabic term which designates it as The Foot of Orion. Orion’s Belt points up towards Aldebaran at the edge of the photograph and down towards Sirius among the branches of the trees; it is the brightest star in the night sky and is located in the constellation Canis Major. Earth’s atmosphere makes the bright Sirius twinkle in all colours. Seen from space it is pure white, but as its light travels through the air, it is scattered and distorted by the molecules. Therefore, the star appears to change colour like a diamond. A line connecting the two shoulders of Orion points to another bright star in the lower-left corner of the photograph. This is Procyon, located in the constellation Canis Minor. Procyon has been used by the ancient Babylonians to indicate the heliacal rise of Cancer (whose stars are faint, and invisible in twilight) and to predict the rising of Sirius. Thus, for a very long time in ancient history Procyon was considered a single-star asterism. Perhaps only in Roman times were more stars used to create a constellation in this area of the sky, although this constellation has never been clearly recognisable.
Credit: René Antonio Urroz Álvarez/IAU OAE

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Five bright stars form the shape of the letter M.

Portrait of a Bat

Caption: Honourable mention in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.   Taken in November 2019 from the Doi Inthanon National Park, Chiang Mai, Thailand, this image captures the notable northern constellation Cassiopeia, in the shape of the letter M. Although the official constellation name is the Latinised version of the name of queen “Kasseipeia” from Greek mythology, these five bright stars were considered a constellation in many cultures around the world and they are associated with diverse stories. In Thailand, for example, the constellation represents a Bat, while in Hawaiian culture it is called 'Iwa Keli'i, the chief frigate bird. For the Navajo in North America, the bright stars are the central part of the celestial mother (of all stars and humans) revolving around the celestial pole together with her husband, the celestial father (of all stars and humans) seen in the constellation of Ursa Major. For the Maya it was part of the huge constellation of the Hole-Backed Caiman, and for the Inuit a Lamp Stand and a Blubber Container. In ancient China, the bottom-left star was associated with the mythological general Wangliang who drove four horses, represented by the two bright and two fainter stars of the M’s next stroke (from upper-left to lower-middle). The remaining two bright stars and a couple of the other fainter ones are considered a Flying Corridor, a sort of highway, next to the Emperor’s Forbidden Palace that is located at the northern polar region. On the island of Tonga in the South Pacific, this asterism is considered the Wing of Tafahi and it is not clear if this refers to the shape of the island of Tafahi, or if it is based on an error and originally referred to a wing of the Polynesian hero Tafaki. The various colours of the stars indicate their temperatures, with redder stars being relatively cooler on their surface than blue and white stars.
Credit: Thanakrit Santikunaporn/IAU OAE

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The bright Moon illuminates a beach. Three bright planets form a line below and to the right of the Moon.

To guard the Stars and the Sea Together

Caption: Winner in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns. This image composition is amazing. In the far background of the landscape we see a chain of mountains that seems to mirror the structure of the Milky Way in the sky above. The strong daylight-like colours of the landscape are caused by the Moon, the bright light at the top of the image. Taken in Kinabalu, Malaysia, in February 2019, this image shows the alignment of planets and the Moon, conveying the idea of the ecliptic as the central line of the Zodiac, the plane within which all planets orbit the Sun. The ecliptic is the central line of the Zodiac, so the region of about five to 10 degrees either side of the ecliptic is where the constellations of the Zodiac are located. Starting from the horizon towards the bottom left of the image we can see the planets Venus, Saturn and Jupiter. The planets have different cultural significance for people around the world, and are deeply embedded in social, religious and practical aspects of life. For example, Wardaman traditions of Indigenous Australians associate the planets with ancestor spirits who traverse the Celestial Road (ecliptic). The appearance and disappearance of planets in the sky are associated with various ceremonies. For example, when Venus starts being the “Morning star” after having been the “Evening star”, this marks the Banumbirr ceremony for the Yolnu people of Arnhem Land, in Australia. The image also shows the constellations Scorpius, Aquila, Lupus and Triangulum Australe, the asterism of the Teapot, and the two pointer stars Alpha and Beta Centauri. The constellations, asterisms and individual stars within them have significance in many different cultures. Malaysia, being close to the equator, has had connections to the north as well as to the south and almost the whole sky is visible over the course of the year. The star Antares is seen by the Kokatha people of the Western Desert as Kogolongo, the red tailed black cockatoo, while the Boorong refer to it as Djuit, the red-rumped parrot. The two stars which form the stinger of Scorpius (Shaula and Lesath), are called Karik Karik, the Australian Kestrel.
Credit: Likai Lin/IAU OAE

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The diffuse glow of the Milky Way broken by dark patches. Right, the red star Antares forms the top of a hook-like pattern

Milky Way Arch over La Palma

Caption: Winner in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.   This image, which shows the majestic band of the Milky Way and a range of culturally significant patterns, was taken in May 2022 at a very high altitude from the Roque de los Muchachos Observatory in La Palma, from which one can see the clouds below. Some prominent star patterns include Scorpius, Sagittarius, Lyra, Cygnus, Aquila, the Summer Triangle asterism, and the Teapot asterism. As the Canary Islands used to be a starting point for European sailors to explore the world, we use this place to point to the many indigenous cultures they encountered. Most notably it is the dark patterns within the band of the Milky Way that hold significance for many Indigenous cultures around the world. The dark patterns are in fact dense, cool clouds of gas and dust that block the light from stars. Indigenous people see caves, waterways and various patterns associated with the dark regions of the Milky Way. The constellations and patterns hold different cultural significance and interpretations for different people. For example, the constellation Scorpius is referred to by Polynesian people as the demigod Maui’s Fishhook. The Yolnu people of Arnhem Land associate Scorpius with a crocodile called Ingalpir. Some Indigenous Australian groups associate stories with individual stars within Scorpius, most notably Antares, the orange-red star in the top right of the image above the band of the Milky Way. Next to the Scorpion and above the bright centre of the Milky Way, there is a prominent dark cloud that is called the Pipe Nebula by modern astrophotographers. The smoke of this pipe goes up to rho Ophiuchi. This and all the other dark clouds in the Milky Way together form the backbone of heaven for some tribes, and an animal with black-and-white skin for South African Zulu people. The nomenclature of bright stars also has cross-cultural roots. For example, Vega (the bright blue star towards the top of the image) comes from the Arabic waqi, from al-nasr al-waqi, the Eagle who throws himself down (in order to hunt). This contrasts with the Flying Eagle, Altair, also derived from Arabic. Antares is a Greek word meaning “the one similar to Mars”, referring to its colour. The star name Shaula in the stinger of the Scorpion is a modern version of the Babylonian or even Sumerian star name.
Credit: Amirreza Kamkar/IAU OAE

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Orion appears as an hourglass shape of stars in the bottom of the image. Above Taurus is v-shaped with a small star cluster

Romanian Orion

Caption: Winner in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.   Taken in Romania in August 2012, this image shows two of the most recognisable constellations in the sky, Orion and Taurus. Orion, the Hunter, is found near the horizon. The most prominent star visible in this image is Betelgeuse, while the asterism of Orion’s belt is formed by three aligned bright stars. Just above Orion we can find Taurus, one of the constellations of the Zodiac. As the Zodiac is inherited from Babylon, The Bull of Heaven represents a mighty but dangerous creature that was defeated by King Gilgamesh and his friend Enkidu. They cut the Bull in half and sacrificed the animal to the gods in order to protect their people. Taurus is also home to the star cluster Pleiades, also known as the Seven Sisters. Two planets are visible: Venus, the bright spot near the fence, and Jupiter, the bright spot at the top, next to the Bull’s face. Different cultures have included the stars of these constellations in their own mythology. The Romanians, for instance, after Christianisation identified four other constellations using some of the stars of Orion and others surrounding it. One such constellation is called Trisfetitele (the Three Saints), which is associated with the three stars comprising Orion's Belt, representing the Three Hierarchs Basil, Gregory and John. This same asterism is also called Three Wise Men, Kings from the East or just Three Kings — all of these names being rooted in the Christian religion. The agricultural calendar, in contrast, led farmers to define two other constellations, the Little Plough and the Sickle. Both are seen in the southern half of the Orion rectangle; the Little Plough is drawn by connecting the southern quadrilateral with Orion’s left shoulder, and the Sickle is formed by connecting Orion’s left foot (Rigel) with the belt stars, forming an arch and completing the form of a hoe. In the cultural calendar, these constellations were used to announce the harvest of wheat/grain. Finally, the fourth Romanian constellation is the Great Auger, where Orion’s belt represents the handle of the auger, and Betelgeuse is the tip, facing towards Pollux in Gemini. This constellation is associated with treasure, as Romanian peasants believe that the Auger points to the treasure when they approach the end of the world. Most of the official star names in Orion are Arabic; Mintaka (meaning “belt”) is at the waist; Alnitak (meaning “girdle”) and Alnilam (meaning “string”) are at the belt; and Rigel (meaning foot) is at the left foot. The star on the left shoulder is named Bellatrix, the Latin term for a female warrior. The star at the right leg is called Saiph, for the sword or sabre of the Arabic Orion.
Credit: Alex Conu/IAU OAE

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Over a watery field, Orion is shaped like a bow-tie turned 45 degrees. The bright star Sirius is in the image's left half

Watchtower and Paddy Fields Under the Starry Sky

Caption: Winner in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.   This image, taken in April 2022, shows the sky over a plantation field around a century-old watchtower guarding a village in the province of Guangdong, China. Throughout the ages, the sky has been used as a tool for navigation and also as a calendar. By watching the apparent movement of the stars, it is possible to follow the passing of time, thereby understanding the change of the seasons which in turn helps to plan out the best timings of agricultural work. The most prominent constellations in this image are Orion and Canis Major, the Great Dog. Commonly associated with a giant hunter in Greek mythology, Orion is followed by his hound in the shape of the constellation Canis Major. In China, the seven bright stars of the constellation Orion are paradoxically called Three Stars (Shen) and this is one of the 28 Lunar Mansions. The Babylonian pre-zodiac, the so-called “Path of the Moon”, had 17 constellations and included Orion (therein named “True Shepherd of the Heavens”). This is not really surprising because, even in the system of the 88 modern constellations, the Moon sometimes stands in the constellation Orion. The modern constellation boundaries were defined in the 1920s in such a way that the area of Orion ends a half degree south of the ecliptic, in order to avoid the Sun entering it. Still, the Moon and the planets do occasionally. Therefore, Orion is part of the Zodiac (a stripe 5 to 10 degrees around the ecliptic), part of the path of the Moon and, of course, also used by many cultural calendars all over the world. Sirius, the bright star in the left half of the photograph, is the brightest star in the night sky, and has been used by many indigenous cultures to determine their calendars; the Egyptians awaited the Nile flood with Sirius’s heliacal rise, while the Romans connected its reappearance after its invisibility in daylight with the hottest summer time. In Old China, Sirius was considered a single-star asterism called The Wolf. The adjacent area was called The Market for Soldiers and the area in the southern part of Canis Major was imagined as the Bow with an Arrow. The reddish bright star in the top right corner is Betelgeuse, a red supergiant and one of the largest stars that can be seen with the naked eye. Orion’s Great Nebula below Orion’s Belt should be mentioned, but also the fainter huge red arc that is called Barnard’s Loop is clearly shown in this photograph. This galactic nebula and the circular red nebula around Orion’s not-so-bright head are both parts of star-forming regions, while the red nebula to the upper left of Orion is the Rosette Nebula in the unrecognisable constellation of Monoceros.
Credit: Likai Lin/IAU OAE

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Orion appears as an hourglass with its belt slightly tilted relative to the horizon. The bright star Sirius is bottom-left

Winter Constellations

Caption: Winner in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns. Taken from the Kottamia Astronomical Observatory, Cairo, Egypt, in December 2021, this image shows a few prominent winter constellations of the northern sky above the largest telescope in North Africa. The photograph depicts the constellation of Orion (prominently in the middle of the image) with its belt of stars pointing up to Aldebaran in Taurus and down to Sirius in Canis Major. Aldebaran is a reddish star that we see in front of the open star cluster of the Hyades (at the upper right edge of the image), which is the face of Taurus, the bull. The bright white star is Sirius, the brightest star in the night sky. Its Greek name (Seirios) means “the burner” and can be understood metaphorically as “the brightest”. This constellation has been represented in a variety of different cultures from all over the world. The ancient Egyptian religion also associates the constellation of Orion with a male figure, namely the god Osiris. It is told that Osiris was murdered by his envious brother Seth, who then dismembered the body and scattered the pieces all over the land. Fortunately, Osiris’s sister-wife Aset (Greek: Isis) is the most powerful sorceress and protective mother goddess. She collected the pieces, put them back together and breathed life back into the god. Aset is seen in the star pattern around the bright star Sirius at the bottom of the photograph. The Egyptian name for Sirius (and adjacent areas) is Sopdet (Greek: Sothis). The heliacal rise of Sirius in summer was a harbinger of the Egyptian new year.  Going north, we can spot a bluish star. This is Alhena, one of the stars in the feet of the zodiacal constellation Gemini, the twins, whose bright head stars would be beyond the upper left edge of the photograph. In the top centre we can see the star Elnath, in the constellation of Auriga, the charioteer. It is associated with Erichthonius, a hero of Greek mythology believed to be the inventor of the four-horse chariot. This same star is also considered the tip of the upper horn of Taurus, the bull. In Greek mythology Taurus is associated with the god Zeus who had sent him to rob a princess. It is commonly known that this Greek story was invented in order to include the Babylonian constellation in Greek mythology. In the Mesopotamian Gilgamesh saga, which is one of the oldest pieces of literature that we know (being traced back to the 3rd millennium), Taurus is the bull of heaven, sent by a jealous goddess and defeated by the king of Uruk to save his people. In the sky it harbours several interesting astronomical objects.
Credit: Mohamed Aboushelib/IAU OAE

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The bright stars in Orion trace a shape similar to a bow tie, here tilted by 45 degrees in-front is a ruined building

The Kingdom of Orion

Caption: Winner in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns. This image, taken in January 2022, pictures a landscape from Navarra, a province in the north of Spain with ruins from old civilizations in the foreground. Above that, we see a partially cloudy and starry sky with the most prominent stars belonging to the star pattern Orion. Composed of many bright stars with several interesting deep sky objects within its boundaries, Orion is one of the 88 officially recognised IAU constellations. It originates from Greek mythology where the hero Orion is the son of the sea god Poseidon. Orion is characterised as a giant hunter lurking just before he attacks an animal (it is unclear which animal he attacks, but, in the original Babylonian version of the Gilgamesh saga, it is the Bull of Heaven depicted as the constellation Taurus). The modern planetarium interpretation depicts him as a Roman warrior raising up his shield, but the two accompanying dogs, represented by the constellations of Canis Major and Canis Minor, are reminiscent of the Greek hunter. Located at the celestial equator, the star pattern is visible all over the world and is interpreted differently in various mythologies, for example as three fishermen at a campfire in parts of Australia, as a butterfly in some parts of Africa, and as a stairway for the souls of ancestors in parts of South America. As Spain belonged to the Roman empire, the original constellations from earlier times are not known. There are some cave paintings on the Iberian peninsula that could possibly have astronomical references. However, there is uncertainty as to whether these painted figures on rocks depict star patterns. Orion is best visible from November to January. Its most recognisable feature is the “belt”, an asterism composed of three bright, aligned stars (Alnitak, Alnilam and Mintaka), also recognised by different cultures. Just below this belt is the Orion Nebula, a famous and widely studied star-forming region located about 1500 light-years from Earth. The constellation's brightest stars are Rigel — a blue supergiant which is one of the brightest stars in the sky — and Betelgeuse — a massive red supergiant. The former serves as the left foot, and the latter as the right shoulder of the hunter. While Rigel is in the middle of its life, Betelgeuse is expected to explode within the next few tens of thousands of years. The Orionids, a meteor shower with typical rates of dozens of meteors per hour, whose parent body is Halley’s Comet, can be seen every year in the area of Orion, next to the border with the constellation of Gemini during the month of October.
Credit: Carlos Zudaire/IAU OAE

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Related Diagrams


The bright stars in Andromeda form a Y-shape. Pegasus to the lower right. In the center is M31, marked with a red ellipse.

Andromeda Constellation Map

Caption: The constellation Andromeda showing the bright stars and surrounding constellations. Andromeda is surrounded by (going clockwise from the top) Cassiopeia, Lacerta, Pegasus, Pisces, Aries, Triangulum and Perseus. The brightest star in Andromeda (Alpheratz) is in the lower part of the constellation. Together with three stars in Pegasus it forms the asterism known as the "Great Square of Pegasus". The next two bright stars in the constellation (Mirach and Almach) form a line extending north-east from Alpheratz. Andromeda is a northern constellation and is most visible in the evenings in the Northern Hemisphere autumn. It is visible from all of the Northern Hemisphere and most temperate regions of the Southern Hemisphere but is not visible from Antarctic and Subantarctic regions. The most famous object in Andromeda, the Andromeda Galaxy is marked here with a red ellipse and its Messier catalog number M31. The yellow circle on the left marks the position of the open cluster NGC 752 and the green circle on the right marks NGC 7662 (the blue snowball nebula), a planetary nebula. 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

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Orion appears as an hourglass-shaped pattern with two strings of stars extending northeast and northwest

Orion Constellation Map

Caption: The constellation Orion along with its bright stars and surrounding constellations. Orion is surrounded by (going clockwise from the top) Taurus, Eridanus, Lepus, Monoceros and Gemini. Orion’s brightest stars Betelgeuse and Rigel appear at the northern (upper on this diagram) and southern (lower) end of the constellation respectively with the famous three star “belt” in the middle. Orion 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. Orion is most visible in the evenings in the northern hemisphere winter and southern hemisphere summer. The blue line above Orion marks the ecliptic, the path the Sun appears to travel across the sky over the course of a year. The Sun never passes through Orion, but one can occasionally find the other planets of the Solar System and the Moon in Orion. Just south of Orion’s belt lie two Messier objects M42 (the Orion nebula) and M43, marked by green squares. These nebulae along with M78 (here the green square to the left of the belt) are part of the huge Orion Molecular Cloud Complex. This covers most of the constellation and includes regions where these molecular clouds are collapsing to form young starts. 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 circle around Betelgeuse indicates that it is a variable star. 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

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Sagittarius is shaped like a teapot pouring tea south west. The ecliptic runs WSW to ENE at the top of the constellation

Sagittarius Constellation Map

Caption: The constellation Sagittarius along with its bright stars and surrounding constellations. Sagittarius is surrounded by (going clockwise from the top) Aquila, Scutum, Serpens Cauda, Ophiuchus, Scorpius, Corona Australis, Telescopium, Microscopium and Capricornus. The brighter stars in Sagittarius form a distinctive teapot shape. Sagittarius 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 Sagittarius from mid December to mid January. The other planets of the Solar System can often be found in Sagittarius. Sagittarius lies south of the celestial equator. The famous teapot asterism is visible for all but the most arctic regions of the world but the most southerly parts of the constellation are not visible in northern parts of Asia, Europe and North America. Sagittarius is most visible in the evenings in the northern hemisphere summer and southern hemisphere winter. The supermassive black hole Sagittarius A* which lies at the center of our Milky Way Galaxy is sits on the western (here right-hand) edge of Sagittarius. Due to it covering an area at the center of our Galaxy, Sagittarius is home to many star clusters including open clusters (marked here with yellow circles) and globular clusters (marked here with yellow circles with + signs superimposed on them). Three nebulae are also marked here with green squares. 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


Scorpius appears as a letter T joined to a letter J. The ecliptic runs ESE to WNW and clips one arm of the T

Scorpius Constellation Map

Caption: The constellation Scorpius (often commonly called Scorpio) along with its bright stars and surrounding constellations. Scorpius is surrounded by (going clockwise from the top) Ophiuchus, Serpens Caput, Libra, Lupus, Norma, Ara, Corona Australis and Sagittarius. Scorpius’s brightest star Antares appears in the heart of the constellation with the famous tail of Scoprius in the south-east (lower left). Scorpius 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 only spends a short amount of time in late November in Scorpius. The other planets of the Solar System can often be found in Scorpius. Scorpius lies south of the celestial equator. The whole constellation is not visible from the most arctic regions of the world with parts of Scorpius obscured for observers in northern parts of Asia, Europe and North America. Scorpius is most visible in the evenings in the northern hemisphere summer and southern hemisphere winter. The yellow circles mark the positions of the open clusters M6, M7 & NGC 6231 while the yellow circles with plus signs superimposed on them mark the globular clusters M4 and M80. 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 circle around Antares indicates that it is a variable star. 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