![Cr399](https://upload.wikimedia.org/wikipedia/commons/5/53/Cr399.jpg)
An asterism is an
observed pattern or group of
stars in the
sky
The sky is an unobstructed view upward from the surface of the Earth. It includes the atmosphere and outer space. It may also be considered a place between the ground and outer space, thus distinct from outer space.
In the field of astronomy, ...
. Asterisms can be any identified pattern or group of stars, and therefore are a more general concept than the
formally defined 88 constellations
A constellation is an area on the celestial sphere in which a group of visible stars forms a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object.
The origins of the earliest constellation ...
. Constellations are based on asterisms, but unlike asterisms, constellations outline and today completely divide the sky and all its celestial objects into regions around their central asterisms.
For example, the asterism known as the
Big Dipper
The Big Dipper ( US, Canada) or the Plough ( UK, Ireland) is a large asterism consisting of seven bright stars of the constellation Ursa Major; six of them are of second magnitude and one, Megrez (δ), of third magnitude. Four define a "bowl" ...
comprises the seven brightest stars in the constellation
Ursa Major
Ursa Major (; also known as the Great Bear) is a constellation in the northern sky, whose associated mythology likely dates back into prehistory. Its Latin name means "greater (or larger) bear," referring to and contrasting it with nearby Ursa ...
. Another is the asterism of the
Southern Cross
Crux () is a constellation of the southern sky that is centred on four bright stars in a cross-shaped asterism commonly known as the Southern Cross. It lies on the southern end of the Milky Way's visible band. The name ''Crux'' is Latin for ...
, within the constellation of
Crux
Crux () is a constellation of the southern sky that is centred on four bright stars in a cross-shaped asterism commonly known as the Southern Cross. It lies on the southern end of the Milky Way's visible band. The name ''Crux'' is Latin for ...
.
Asterisms range from simple shapes of just a few stars to more complex collections of many stars covering large portions of the sky. The stars themselves may be bright naked-eye objects or fainter, even telescopic, but they are generally all of a similar brightness to each other. The larger brighter asterisms are useful for people who are familiarizing themselves with the night sky.
The patterns of stars seen in asterisms are not necessarily a product of any physical association between the stars, but are rather the result of the particular perspectives of their observations. For example the
Summer Triangle is a purely observational physically unrelated group of stars, but the stars of
Orion's Belt
Orion's Belt or the Belt of Orion, also known as the Three Kings or Three Sisters, is an asterism in the constellation Orion. It consists of the three bright stars Alnitak, Alnilam and Mintaka.
Looking for Orion's Belt is the easiest way to ...
are all members of the
Orion OB1 association
Orion OB1 (Ori OB1) is a contingent group of several dozen hot giant stars of spectral types O and B in Orion. Associated are thousands of lower-mass stars, and a (smaller but significant) number of protostars. It is part of the larger Orion mo ...
and five of the seven stars of the Big Dipper are members of the
Ursa Major Moving Group. Physical associations, such as the
Hyades Hyades may refer to:
* Hyades (band)
*Hyades (mythology)
*Hyades (star cluster)
The Hyades (; Greek Ὑάδες, also known as Caldwell 41, Collinder 50, or Melotte 25) is the nearest open cluster and one of the best-studied star clusters. Loca ...
or
Pleiades
The Pleiades (), also known as The Seven Sisters, Messier 45 and other names by different cultures, is an asterism and an open star cluster containing middle-aged, hot B-type stars in the north-west of the constellation Taurus. At a distance ...
, can be asterisms in their own right and part of other asterisms at the same time.
Background of asterisms and constellations
In many early civilizations, it was already common to associate groups of stars in
connect-the-dots
Connect the dots (also known as connect-the-dots, dot to dot, or join the dots) is a form of puzzle containing a sequence of numbered dots. When a line is drawn connecting the dots the outline of an object is revealed. The puzzles frequently c ...
stick-figure patterns; some of the earliest records are those of ancient India in the
Vedanga Jyotisha
Vedanga Jyotisha (), or Jyotishavedanga (), is one of earliest known Indian texts on astrology (''Jyotisha''). The extant text is dated to the final centuries BCE, but it may be based on a tradition reaching back to about 700-600 BCE.
The text ...
and the
Babylonians
Babylonia (; Akkadian: , ''māt Akkadī'') was an ancient Akkadian-speaking state and cultural area based in the city of Babylon in central-southern Mesopotamia (present-day Iraq and parts of Syria). It emerged as an Amorite-ruled state c. 1 ...
. This process was essentially arbitrary, and different cultures have identified different constellations, although a few of the more obvious patterns tend to appear in the constellations of multiple cultures, such as those of
Orion and
Scorpius
Scorpius is a zodiac constellation located in the Southern celestial hemisphere, where it sits near the center of the Milky Way, between Libra to the west and Sagittarius to the east. Scorpius is an ancient constellation that pre-dates the Gr ...
. As anyone could arrange and name a grouping of stars there was no distinct difference between a ''constellation'' and an ''asterism''. e.g.
Pliny the Elder
Gaius Plinius Secundus (AD 23/2479), called Pliny the Elder (), was a Roman author, naturalist and natural philosopher, and naval and army commander of the early Roman Empire, and a friend of the emperor Vespasian. He wrote the encyclopedic ' ...
(23–79 AD) in his book
Naturalis Historia
The ''Natural History'' ( la, Naturalis historia) is a work by Pliny the Elder. The largest single work to have survived from the Roman Empire to the modern day, the ''Natural History'' compiles information gleaned from other ancient authors. ...
refers and mentions 72 asterisms.
A general list containing 48 constellations likely began to develop with the astronomer
Hipparchus
Hipparchus (; el, Ἵππαρχος, ''Hipparkhos''; BC) was a Greek astronomer, geographer, and mathematician. He is considered the founder of trigonometry, but is most famous for his incidental discovery of the precession of the equi ...
(c. 190 – c. 120 BC ), and was mostly accepted as standard in Europe for 1,800 years. As constellations were considered to be composed only of the stars that constituted the figure, it was always possible to use any leftover stars to create and squeeze in a new grouping among the established constellations.
Furthermore, exploration by Europeans to other parts of the globe exposed them to stars unknown to them. Two astronomers particularly known for greatly expanding the number of southern constellations were
Johann Bayer (1572–1625) and
Nicolas Louis de Lacaille
Abbé Nicolas-Louis de Lacaille (; 15 March 171321 March 1762), formerly sometimes spelled de la Caille, was a French astronomer and geodesist who named 14 out of the 88 constellations. From 1750 to 1754, he studied the sky at the Cape of Goo ...
(1713–1762). Bayer had listed twelve figures made out of stars that were too far south for Ptolemy to have seen; Lacaille created 14 new groups, mostly for the area surrounding
South Celestial Pole. Many of these proposed constellations have been formally accepted, but the rest have historically remained as asterisms.
In 1928, the
International Astronomical Union
The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...
(IAU) precisely divided the sky into
88 official constellations following geometric boundaries encompassing all of the stars within them. Any additional new selected groupings of stars or
former constellation
Former constellations are old historical Western constellations that for various reasons are no longer widely recognised or are not officially recognised by the International Astronomical Union (IAU). Prior to 1930, many of these defunct const ...
s are often considered as asterisms. However, depending on the particular literature source, any technical distinctions between the terms 'constellation' and 'asterism' often remain somewhat ambiguous.
Asterisms consisting of first-magnitude stars
Some asterims consist completely of bright
first-magnitude stars, which mark out simple geometric shapes.
* The ''
Summer Triangle'' of
Deneb
Deneb () is a first-magnitude star in the constellation of Cygnus, the swan. Deneb is one of the vertices of the asterism known as the Summer Triangle and the "head" of the Northern Cross. It is the brightest star in Cygnus and th ...
,
Altair
Altair is the brightest star in the constellation of Aquila and the twelfth-brightest star in the night sky. It has the Bayer designation Alpha Aquilae, which is Latinised from α Aquilae and abbreviated Alpha Aql ...
, and
Vega
Vega is the brightest star in the northern constellation of Lyra. It has the Bayer designation α Lyrae, which is Latinised to Alpha Lyrae and abbreviated Alpha Lyr or α Lyr. This star is relatively close at only from the Sun, a ...
– α
Cygni, α
Aquilae, and α
Lyra
Lyra (; Latin for lyre, from Greek ''λύρα'') is a small constellation. It is one of the 48 listed by the 2nd century astronomer Ptolemy, and is one of the modern 88 constellations recognized by the International Astronomical Union. Lyra wa ...
e – is prominent in the northern hemisphere summer skies, as its three stars are all of the 1st magnitude.
The stars of the Triangle are in the band of the
Milky Way
The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. ...
which marks the galactic equator, and are in the direction of the galactic center.
* The ''
Winter Hexagon
The Winter Hexagon or Winter Circle/Oval is an asterism appearing to be in the form of a hexagon with vertices at Rigel, Aldebaran, Capella, Pollux, Procyon, and Sirius. It is mostly upon the Northern Hemisphere's celestial sphere. On most ...
'' includes seven of the twenty-two first-magnitude stars visible in the sky, with
Pollux,
Capella
Capella is the brightest star in the northern constellation of Auriga. It has the Bayer designation α Aurigae, which is Latinised to Alpha Aurigae and abbreviated Alpha Aur or α Aur. Capella is the sixth-brightest star in ...
,
Aldebaran
Aldebaran (Arabic: “The Follower”, "الدبران") is the brightest star in the zodiac constellation of Taurus. It has the Bayer designation α Tauri, which is Latinized to Alpha Tauri and abbreviated Alpha Tau or α Tau. Alde ...
,
Rigel
Rigel is a blue supergiant star in the constellation of Orion. It has the Bayer designation β Orionis, which is Latinized to Beta Orionis and abbreviated Beta Ori or β Ori. Rigel is the brightest and most massive componentand ...
,
Sirius
Sirius is the brightest star in the night sky. Its name is derived from the Greek word , or , meaning 'glowing' or 'scorching'. The star is designated α Canis Majoris, Latinized to Alpha Canis Majoris, and abbreviated Alpha CM ...
and
Procyon
Procyon () is the brightest star in the constellation of Canis Minor and usually the eighth-brightest star in the night sky, with an apparent visual magnitude of 0.34. It has the Bayer designation α Canis Minoris, which is Latinized ...
(the second and fourth
closest star visible without aid), and with the 2nd-magnitude
Castor on the periphery, and
Betelgeuse off-center.
It is also known as the ''Heavenly 'G.
It encircles the
galactic anticenter
The galactic anticenter is a direction in space directly opposite to the Galactic Center, as viewed from Earth. This direction corresponds to a point on the celestial sphere.
From the perspective of an observer on Earth, the galactic anticenter ...
, as well as incorporates constellations such as
Gemini
Gemini may refer to:
Space
* Gemini (constellation), one of the constellations of the zodiac
** Gemini in Chinese astronomy
* Project Gemini, the second U.S. crewed spaceflight program
* Gemini Observatory, consisting of telescopes in the Norther ...
and
Orion. It also includes in the background of Aldebaran the
Hyades Hyades may refer to:
* Hyades (band)
*Hyades (mythology)
*Hyades (star cluster)
The Hyades (; Greek Ὑάδες, also known as Caldwell 41, Collinder 50, or Melotte 25) is the nearest open cluster and one of the best-studied star clusters. Loca ...
, the nearest
star cluster and one of five first-magnitude
deep-sky object
A deep-sky object (DSO) is any astronomical object that is not an individual star or Solar System object (such as Sun, Moon, planet, comet, etc.). The classification is used for the most part by amateur astronomers to denote visually observed f ...
s, two of which can be seen just north-east of the Hyades, the
Pleiades
The Pleiades (), also known as The Seven Sisters, Messier 45 and other names by different cultures, is an asterism and an open star cluster containing middle-aged, hot B-type stars in the north-west of the constellation Taurus. At a distance ...
also in the
Taurus constellation and the
Alpha Persei Cluster
The Alpha Persei Cluster, also known as Melotte 20 or Collinder 39, is an open cluster of stars in the northern constellation of Perseus. To the naked eye, the cluster consists of several blue-hued spectral type B stars. The most luminous member ...
(with
Alcyone and
Mirfak as the brightest stars).
** Part of the Winter Hexagon the ''
Winter Triangle
The Winter Triangle is an astronomical asterism formed from three of the brightest stars in the winter sky. It is an imaginary equilateral triangle drawn on the celestial sphere, with its defining vertices at Sirius, Betelgeuse, and Procyon, the ...
'' is visible in the northern sky's winter and comprises the first magnitude stars Procyon, Betelgeuse and Sirius.
* The ''
Spring Triangle
The Spring Triangle is an astronomical asterism involving an imaginary triangle drawn upon the celestial sphere, with its defining vertices at Arcturus, Spica, and Regulus. This triangle connects the constellations of Boötes, Virgo, and Leo. ...
'' consists of
Arcturus
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, Note (category: variability): , , H and K emission vary.
Arcturus is the brightest star in the northern constellation of Boötes. With an apparent visual magnitude of −0.05, it is the third-brightest of the ...
,
Regulus
Regulus is the brightest object in the constellation Leo and one of the brightest stars in the night sky. It has the Bayer designation designated α Leonis, which is Latinized to Alpha Leonis, and abbreviated Alpha Leo or α Leo. Reg ...
and
Spica
Spica is the brightest object in the constellation of Virgo and one of the 20 brightest stars in the night sky. It has the Bayer designation α Virginis, which is Latinised to Alpha Virginis and abbreviated Alpha Vir or α Vir. Analys ...
.
** The ''
Great Diamond'' consisting of Arcturus, Spica,
Denebola
Denebola is the second-brightest star in the zodiac constellation of Leo.The two components of the γ Leonis double star, which are unresolved to the naked eye, have a combined magnitude brighter than it. It has the Bayer designatio ...
and
Cor Caroli
Cor Caroli is a binary star designated Alpha Canum Venaticorum or α Canum Venaticorum. The International Astronomical Union uses the name "Cor Caroli" specifically for the brighter star of the binary. Alpha Canum Venaticorum is the brig ...
, the latter two not being first-magnitude stars.
[AstronomyOnline: Image of ''Big Dipper'', ''Diamond of Virgo'', ''The Sail'', ''Sickle'', and ''Asses'' and the ''Manger''](_blank)
Astronomyonline.org An east-west line from Arcturus to Denebola forms an equilateral triangle with Cor Caroli to the North, and another with Spica to the South. Together these two triangles form the Diamond. Formally, the stars of the Diamond are in the constellations
Boötes,
Virgo
Virgo may refer to:
*Virgo (astrology), the sixth astrological sign of the zodiac
* Virgo (constellation), a constellation
*Virgo Cluster, a cluster of galaxies in the constellation Virgo
*Virgo Stellar Stream, remains of a dwarf galaxy
* Virgo Su ...
,
Leo, and
Canes Venatici
Canes Venatici () is one of the 88 constellations designated by the International Astronomical Union (IAU). It is a small northern constellation that was created by Johannes Hevelius in the 17th century. Its name is Latin for 'hunting dogs', and ...
.
Other asterisms consist partially of multiple first-magnitude stars.
*The ''
Southern Cross
Crux () is a constellation of the southern sky that is centred on four bright stars in a cross-shaped asterism commonly known as the Southern Cross. It lies on the southern end of the Milky Way's visible band. The name ''Crux'' is Latin for ...
'' including the first-magnitude stars
Acrux
Acrux is the brightest star in the southern constellation of Crux. It has the Bayer designation α Crucis, which is Latinised to Alpha Crucis and abbreviated Alpha Cru or α Cru. With a combined visual magnitude of +0.76, it is the 1 ...
and
Mimosa
''Mimosa'' is a genus of about 590 species of herbs and shrubs, in the mimosoid clade of the legume family Fabaceae. The generic name is derived from the Greek word (''mimos''), an "actor" or "mime", and the feminine suffix -''osa'', "resemb ...
, west of the
Carina Nebula (one of five first-magnitude deep-sky objects), and with the first-magnitude stars
Alpha Centauri (the
closest star to the Sun) and
Beta Centauri
Beta Centauri is a triple star system in the southern constellation of Centaurus. It is officially called Hadar (). The Bayer designation of Beta Centauri is Latinised from β Centauri, and abbreviated Beta Cen or β Cen. The sys ...
pointing at the cross, distinguishing the cross from less bright and similar asterisms like the
Diamond Cross or
False Cross
An asterism is an observational astronomy, observed pattern or group of stars in the sky. Asterisms can be any identified pattern or group of stars, and therefore are a more general concept than the IAU designated constellations, formally defined ...
.
All other first-magnitude stars are the only such stars in their asterisms or constellations, with
Canopus
Canopus is the brightest star in the southern constellation of Carina and the second-brightest star in the night sky. It is also designated α Carinae, which is Latinised to Alpha Carinae. With a visual apparent magnitude ...
in the
Argo Navis
Argo Navis (the Ship Argo), or simply Argo, is one of the 48 Ptolemy's constellations, now a grouping of three IAU constellations. It is formerly a single large constellation in the southern sky. The genitive is "Argus Navis", abbreviated "Arg" ...
asterism south of Sirius, visually east of the Carina Nebula and near the
Large Magellanic Cloud (both being first-magnitude deep-sky objects),
Achernar in the
Eridanus constellation east of Canopus,
Fomalhaut
Fomalhaut is the brightest star in the southern constellation of Piscis Austrinus, the "Southern Fish", and one of the brightest stars in the night sky. It has the Bayer designation Alpha Piscis Austrini, which is Latinized from � ...
in the
Southern Fish constellation east of Achernar and
Antares
Antares is the brightest star in the constellation of Scorpius. It has the Bayer designation α Scorpii, which is Latinised to Alpha Scorpii. Often referred to as "the heart of the scorpion", Antares is flanked by σ Scorpii and τ ...
in the
Scorpius
Scorpius is a zodiac constellation located in the Southern celestial hemisphere, where it sits near the center of the Milky Way, between Libra to the west and Sagittarius to the east. Scorpius is an ancient constellation that pre-dates the Gr ...
constellation visually near the
Galactic Center
The Galactic Center or Galactic Centre is the rotational center, the barycenter, of the Milky Way galaxy. Its central massive object is a supermassive black hole of about 4 million solar masses, which is called Sagittarius A*, a compact ra ...
.
Constellation-based asterisms
![Plough big dipper](https://upload.wikimedia.org/wikipedia/commons/3/37/Plough_big_dipper.svg)
* The ''
Big Dipper
The Big Dipper ( US, Canada) or the Plough ( UK, Ireland) is a large asterism consisting of seven bright stars of the constellation Ursa Major; six of them are of second magnitude and one, Megrez (δ), of third magnitude. Four define a "bowl" ...
'', also known as ''The Plough'' or ''Charles's Wain'', is composed of the seven brightest stars in
Ursa Major
Ursa Major (; also known as the Great Bear) is a constellation in the northern sky, whose associated mythology likely dates back into prehistory. Its Latin name means "greater (or larger) bear," referring to and contrasting it with nearby Ursa ...
.
These stars delineate the Bear's hindquarters and exaggerated tail,
or alternatively, the "handle" forming the upper outline of the bear's head and neck. With its longer tail,
Ursa Minor
Ursa Minor (Latin: 'Lesser Bear', contrasting with Ursa Major), also known as the Little Bear, is a constellation located in the far northern sky. As with the Great Bear, the tail of the Little Bear may also be seen as the handle of a ladle, ...
hardly appears bearlike at all, and is widely known by its pseudonym, the ''Little Dipper''.
* The
''Northern Cross'' in
Cygnus.
The upright runs from
Deneb
Deneb () is a first-magnitude star in the constellation of Cygnus, the swan. Deneb is one of the vertices of the asterism known as the Summer Triangle and the "head" of the Northern Cross. It is the brightest star in Cygnus and th ...
(α Cyg) in the Swan's tail to
Albireo
Albireo is a double star designated Beta Cygni (β Cygni, abbreviated Beta Cyg, β Cyg). The International Astronomical Union uses the name "Albireo" specifically for the brightest star in the system. Although designated ' beta', ...
(β Cyg) in the beak. The transverse runs from
ε Cygni
Epsilon Cygni (ε Cygni, abbreviated Epsilon Cyg, ε Cyg) is star system, multiple star system in the constellation of Cygnus (constellation), Cygnus. With an apparent magnitude, apparent visual magnitude of 2.48, it is Bortle scale, read ...
in one wing to
δ Cygni in the other.
* The ''Southern Cross'' is an asterism by name, but the whole area is now recognised as the constellation
Crux
Crux () is a constellation of the southern sky that is centred on four bright stars in a cross-shaped asterism commonly known as the Southern Cross. It lies on the southern end of the Milky Way's visible band. The name ''Crux'' is Latin for ...
. The main stars are
Alpha,
Beta,
Gamma,
Delta
Delta commonly refers to:
* Delta (letter) (Δ or δ), a letter of the Greek alphabet
* River delta, at a river mouth
* D ( NATO phonetic alphabet: "Delta")
* Delta Air Lines, US
* Delta variant of SARS-CoV-2 that causes COVID-19
Delta may also ...
, and arguably also
Epsilon Crucis
Epsilon Crucis, ε Crucis (abbreviated Eps Cru, ε Cru), also known as Ginan , is a single, orange-hued star in the southern constellation of Crux. Measurements made by the Hipparcos spacecraft showed an annual parallax shift of 14.19 ...
. Earlier, Crux ''was'' deemed an asterism when Bayer created it in ''
Uranometria
''Uranometria'' is a star atlas produced by Johann Bayer. It was published in Augsburg in 1603 by Christoph Mangle (''Christophorus Mangus'') under the full title ''Uranometria: omnium asterismorum continens schemata, nova methodo delineata, a ...
'' (1603) from the stars in the hind legs of
Centaurus
Centaurus is a bright constellation in the southern sky. One of the largest constellations, Centaurus was included among the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one of the 88 modern constellations. ...
, decreasing the size of Centaur. These same stars were probably identified by
Pliny the Elder
Gaius Plinius Secundus (AD 23/2479), called Pliny the Elder (), was a Roman author, naturalist and natural philosopher, and naval and army commander of the early Roman Empire, and a friend of the emperor Vespasian. He wrote the encyclopedic ' ...
in his
Naturalis Historia
The ''Natural History'' ( la, Naturalis historia) is a work by Pliny the Elder. The largest single work to have survived from the Roman Empire to the modern day, the ''Natural History'' compiles information gleaned from other ancient authors. ...
as the asterism 'Thronos Caesaris.'
* The ''Fish Hook'' is the traditional Hawaiian name for
Scorpius
Scorpius is a zodiac constellation located in the Southern celestial hemisphere, where it sits near the center of the Milky Way, between Libra to the west and Sagittarius to the east. Scorpius is an ancient constellation that pre-dates the Gr ...
. The image will be even more obvious if the chart's lines from
Antares
Antares is the brightest star in the constellation of Scorpius. It has the Bayer designation α Scorpii, which is Latinised to Alpha Scorpii. Often referred to as "the heart of the scorpion", Antares is flanked by σ Scorpii and τ ...
(α Sco) to
Beta Scorpii
Beta Scorpii (β Scorpii, abbreviated Beta Sco, β Sco) is a multiple star system in the southern zodiac constellation of Scorpius. It bore the traditional proper name of Acrab , though the International Astronomical Union now regards ...
(β Sco) and
Pi Scorpii
Pi Scorpii or π Scorpii, is a triple star system in the southern constellation of Scorpius. With a combined apparent magnitude of 2.9, it can be easily seen with the naked eye. Parallax measurements yield an estimated distance of around ...
(π Sco) are replaced with a line from Beta through
Delta Scorpii
Delta Scorpii ( Latinised from δ Scorpii, abbreviated Delta Sco, δ Sco) is a binary star (the presence of a third star in the system is being debated) in the constellation of Scorpius. The primary star is named Dschubba .
Observation
...
(δ Sco) to Pi forming a large capped "J." Adding vertical lines to connect the limbs at the left and right in the main diagram of
Hercules
Hercules (, ) is the Roman equivalent of the Greek divine hero Heracles, son of Jupiter and the mortal Alcmena. In classical mythology, Hercules is famous for his strength and for his numerous far-ranging adventures.
The Romans adapted the ...
will complete the figure of the Butterfly.
*
Boötes is sometimes known as the ''Ice Cream Cone''. It is also known as the ''Kite''.
* The stars of
Cassiopeia form a W which is often used as a nickname.
* The ''Great Square'' of
Pegasus is the quadrilateral formed by the stars
Markab,
Scheat,
Algenib, and
Alpheratz, representing the body of the winged horse.
[AstronomyOnline: Image of ''Cassiopeia'', ''Square of Pegasus'', ''The Circlet'', and ''Y of Aquarius''](_blank)
Astronomyonline.org The asterism was recognized as the constellation ASH.IKU "The Field" on the
MUL.APIN
MUL.APIN () is the conventional title given to a Babylonian compendium that deals with many diverse aspects of Babylonian astronomy and astrology.
It is in the tradition of earlier star catalogues, the so-called ''Three Stars Each'' lists, but ...
cuneiform
Cuneiform is a logo-syllabic script that was used to write several languages of the Ancient Middle East. The script was in active use from the early Bronze Age until the beginning of the Common Era. It is named for the characteristic wedge-sh ...
tablets from about 1100 to 700 BC.
Some asterisms may also be part of a constellation referring to the traditional figuring of the whole outline, for example ''
Orion's Belt
Orion's Belt or the Belt of Orion, also known as the Three Kings or Three Sisters, is an asterism in the constellation Orion. It consists of the three bright stars Alnitak, Alnilam and Mintaka.
Looking for Orion's Belt is the easiest way to ...
'', and the Y in
Aquarius
Aquarius may refer to:
Astrology
* Aquarius (astrology), an astrological sign
* Age of Aquarius, a time period in the cycle of astrological ages
Astronomy
* Aquarius (constellation)
* Aquarius in Chinese astronomy
Arts and entertainme ...
(historically called ''The Urn'').
Other particular asterisms
![Sagittarius-teapot-asterism](https://upload.wikimedia.org/wikipedia/commons/3/3a/Sagittarius-teapot-asterism.jpg)
Other asterisms are also composed of stars from one constellation, but do not refer to the traditional figures.
* Four other stars (
Beta,
Upsilon
Upsilon (, ; uppercase Υ, lowercase υ; el, ''ýpsilon'' ) or ypsilon is the 20th letter of the Greek alphabet. In the system of Greek numerals, grc, Υʹ, label=none has a value of 400. It is derived from the Phoenician waw .
E ...
,
Theta
Theta (, ; uppercase: Θ or ; lowercase: θ or ; grc, ''thē̂ta'' ; Modern: ''thī́ta'' ) is the eighth letter of the Greek alphabet, derived from the Phoenician letter Teth . In the system of Greek numerals, it has a value of 9.
Gr ...
, and
Omega
Omega (; capital: Ω, lowercase: ω; Ancient Greek ὦ, later ὦ μέγα, Modern Greek ωμέγα) is the twenty-fourth and final letter in the Greek alphabet. In the Greek numeric system/ isopsephy ( gematria), it has a value of 800. The ...
Carina
Carina may refer to:
Places
Australia
* Carina, Queensland, a suburb in Brisbane
* Carina Heights, Queensland, a suburb in Brisbane
* Carina, Victoria, a locality in Mildura
Serbia
* Carina, Osečina, a village in the Kolubara District
...
e) form a well-shaped diamond – the ''
Diamond Cross''.
* The ''Saucepan'' or ''Pot'', being the same stars as the Belt and Sword of Orion. The end of the handle is at
ι Orionis, with the far rim at
η Orionis.
* The four central stars in
Hercules
Hercules (, ) is the Roman equivalent of the Greek divine hero Heracles, son of Jupiter and the mortal Alcmena. In classical mythology, Hercules is famous for his strength and for his numerous far-ranging adventures.
The Romans adapted the ...
,
Epsilon (ε Her),
Zeta
Zeta (, ; uppercase Ζ, lowercase ζ; grc, ζῆτα, el, ζήτα, label= Demotic Greek, classical or ''zē̂ta''; ''zíta'') is the sixth letter of the Greek alphabet. In the system of Greek numerals, it has a value of 7. It was derived f ...
(ζ Her),
Eta
Eta (uppercase , lowercase ; grc, ἦτα ''ē̂ta'' or ell, ήτα ''ita'' ) is the seventh letter of the Greek alphabet, representing the close front unrounded vowel . Originally denoting the voiceless glottal fricative in most dialects, ...
(η Her), and
Pi (π Her), form the ''Keystone''.
* The curve of stars at the front end of the Lion from
Epsilon (ε Leo) to
Regulus
Regulus is the brightest object in the constellation Leo and one of the brightest stars in the night sky. It has the Bayer designation designated α Leonis, which is Latinized to Alpha Leonis, and abbreviated Alpha Leo or α Leo. Reg ...
(α Leo), looking much like a mirror-image question mark, has long been known as the
''Sickle''.
* The brighter stars of
Sagittarius make the ''Teapot''.
(The
Large Sagittarius Star Cloud
The Large Sagittarius Star Cloud is the brightest visible region of the Milky Way galaxy, a portion of the central galactic bulge, bulge seen around the thick dust of the Great Rift (astronomy), Great Rift which lines the northwest edge. It shoul ...
appears to be steam emerging from the "spout".)
* Four bright stars in
Delphinus
Delphinus (Pronounced or ) is a small constellation in the Northern Celestial Hemisphere, close to the celestial equator. Its name is the Latin version for the Greek word for dolphin (). It is one of the 48 constellations listed by the 2nd c ...
(
Sualocin
Alpha Delphini (α Delphini, abbreviated Alpha Del, α Del) is a multiple star system in the constellation of Delphinus.
It consists of a triple star, designated Alpha Delphini A, together with five faint, probably optical compani ...
or α Delphini,
Rotanev
Beta Delphini (β Delphini, abbreviated Beta Del, β Del) is a binary star in the constellation of Delphinus. It is the brightest star in Delphinus.
The two components of the system are designated Beta Delphini A ...
or β Delphini,
γ Delphini and
δ Delphini) form ''Job's Coffin''.
* The
''Terebellum'' is a small quadrilateral of four faint stars (
Omega
Omega (; capital: Ω, lowercase: ω; Ancient Greek ὦ, later ὦ μέγα, Modern Greek ωμέγα) is the twenty-fourth and final letter in the Greek alphabet. In the Greek numeric system/ isopsephy ( gematria), it has a value of 800. The ...
,
59,
60,
62) in
Sagittarius' hindquarters.
* Just south of Pegasus, the western fish of
Pisces
Pisces may refer to:
* Pisces, an obsolete (because of land vertebrates) taxonomic superclass including all fish
* Pisces (astrology), an astrological sign
* Pisces (constellation), a constellation
**Pisces Overdensity, an overdensity of stars in ...
is home to the ''Circlet'' formed from
Gamma (γ Piscium),
Kappa (κ Piscium),
Lambda
Lambda (}, ''lám(b)da'') is the 11th letter of the Greek alphabet, representing the voiced alveolar lateral approximant . In the system of Greek numerals, lambda has a value of 30. Lambda is derived from the Phoenician Lamed . Lambda gave ri ...
(λ Piscium),
TX Piscium
TX Piscium (19 Piscium) is a variable carbon star in the constellation Pisces. It is amongst the reddest naked eye stars, with a significant reddish hue when seen in binoculars. It is approximately 900 light years from Earth.
Spe ...
,
Iota
Iota (; uppercase: Ι, lowercase: ι; ) is the ninth letter of the Greek alphabet. It was derived from the Phoenician letter Yodh. Letters that arose from this letter include the Latin I and J, the Cyrillic І (І, і), Yi (Ї, ї), and ...
(ι Piscium), and
Theta
Theta (, ; uppercase: Θ or ; lowercase: θ or ; grc, ''thē̂ta'' ; Modern: ''thī́ta'' ) is the eighth letter of the Greek alphabet, derived from the Phoenician letter Teth . In the system of Greek numerals, it has a value of 9.
Gr ...
(θ Piscium).
*
Dubhe and
Merak (Alpha and Beta Ursae Majoris), the two stars at the end of the bowl of the
Big Dipper
The Big Dipper ( US, Canada) or the Plough ( UK, Ireland) is a large asterism consisting of seven bright stars of the constellation Ursa Major; six of them are of second magnitude and one, Megrez (δ), of third magnitude. Four define a "bowl" ...
are often called the ''Pointers'': a line from β to α and continued for about five times the distance between them arrives at the North Celestial Pole and the star
Polaris (α UMi/Alpha Ursae Minoris), the North Star.
*
Rigil Kentaurus (α Centauri) and
Hadar (β Centauri) are the ''Southern Pointers'' leading to the Southern Cross and thus helping to distinguish
Crux
Crux () is a constellation of the southern sky that is centred on four bright stars in a cross-shaped asterism commonly known as the Southern Cross. It lies on the southern end of the Milky Way's visible band. The name ''Crux'' is Latin for ...
from the False Cross.
Asterisms across multiple constellations
Other asterisms that are formed from stars in more than one constellation.
* The ''Egyptian X'' is a large asterism which, like the Diamond of Virgo, is composed of a pair of equilateral triangles.
Sirius
Sirius is the brightest star in the night sky. Its name is derived from the Greek word , or , meaning 'glowing' or 'scorching'. The star is designated α Canis Majoris, Latinized to Alpha Canis Majoris, and abbreviated Alpha CM ...
(α CMa),
Procyon
Procyon () is the brightest star in the constellation of Canis Minor and usually the eighth-brightest star in the night sky, with an apparent visual magnitude of 0.34. It has the Bayer designation α Canis Minoris, which is Latinized ...
(α CMi), and
Betelgeuse (α Ori) form one to the North (
Winter Triangle
The Winter Triangle is an astronomical asterism formed from three of the brightest stars in the winter sky. It is an imaginary equilateral triangle drawn on the celestial sphere, with its defining vertices at Sirius, Betelgeuse, and Procyon, the ...
) while Sirius,
Naos (ζ Pup), and
Phakt (α Col) form another to the South. Unlike the Diamond, however, these triangles meet, not base-to-base, but vertex-to-vertex. The name derives from both the shape and, because the stars straddle the Celestial Equator, it is more easily seen from south of the Mediterranean than in Europe.
* The ''Lozenge'' is a small diamond formed from three stars –
Eltanin,
Grumium, and
Rastaban (Gamma, Xi, and Beta Draconis) – in the head of
Draco
Draco is the Latin word for serpent or dragon.
Draco or Drako may also refer to:
People
* Draco (lawgiver) (from Greek: Δράκων; 7th century BC), the first lawgiver of ancient Athens, Greece, from whom the term ''draconian'' is derived
* ...
and one – Iota Herculis – in the foot of
Hercules
Hercules (, ) is the Roman equivalent of the Greek divine hero Heracles, son of Jupiter and the mortal Alcmena. In classical mythology, Hercules is famous for his strength and for his numerous far-ranging adventures.
The Romans adapted the ...
.
* The diamond-shaped ''False Cross'' is composed of the four stars
Alsephina (δ Velorum),
Markeb (κ Velorum),
Avior Avior may refer to:
*Avior Airlines - an airline based in Barcelona, Anzoátegui, Venezuela
*Epsilon Carinae, a star
{{Disambiguation ...
(ε Carinae), and
Aspidiske (ι Carinae).
Although its component stars are not quite as bright as those of the
Southern Cross
Crux () is a constellation of the southern sky that is centred on four bright stars in a cross-shaped asterism commonly known as the Southern Cross. It lies on the southern end of the Milky Way's visible band. The name ''Crux'' is Latin for ...
, it is somewhat larger and better shaped than the Southern Cross, for which it is sometimes mistaken, causing errors in
astronavigation
Celestial navigation, also known as astronavigation, is the practice of position fixing using stars and other celestial bodies that enables a navigator to accurately determine their actual current physical position in space (or on the surface o ...
. Like the Southern Cross, three of its main four stars are whitish and one orange.
* From latitudes above
40 degrees north especially, a prominent upper-case Y is formed by
Arcturus
, - bgcolor="#FFFAFA"
, Note (category: variability): , , H and K emission vary.
Arcturus is the brightest star in the northern constellation of Boötes. With an apparent visual magnitude of −0.05, it is the third-brightest of the ...
(α Boötis),
Seginus (γ Boötis) and
Izar
Navantia is a Spanish state-owned shipbuilding company, which offers its services to both military and civil sectors. It is the fifth-largest shipbuilder in Europe and the ninth-largest in the world with shipyards around the globe. The heir to ...
(ε Boötis), and
Alpha Coronae Borealis
Alpha Coronae Borealis (α Coronae Borealis, abbreviated Alpha CrB, α CrB), officially named Alphecca , is an eclipsing binary star in the constellation of Corona Borealis. It is located about 75 light years from the Sun and contains ...
(Alphecca or Gemma). Alpha Coronae Borealis is far brighter than either Delta or Beta Bootis, distorting the "kite" or "ice-cream cone" shape of Bootes. From the
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...
in particular, where there is serious
light pollution
Light pollution is the presence of unwanted, inappropriate, or excessive use of artificial Visible spectrum, lighting. In a descriptive sense, the term ''light pollution'' refers to the effects of any poorly implemented lighting, during the day ...
in many areas and also
twilight
Twilight is light produced by sunlight scattering in the upper atmosphere, when the Sun is below the horizon, which illuminates the lower atmosphere and the Earth's surface. The word twilight can also refer to the periods of time when this i ...
all night for much of the time these constellations appear, this "Y" is often visible while β and δ Bootis and the other stars in Corona Borealis are not.
* The ''Lightning Bolt'', oriented north to south, consists of the stars
Epsilon Pegasi
Epsilon Pegasi ( Latinised from ε Pegasi, abbreviated Epsilon Peg, ε Peg), formally named Enif , is the brightest star in the northern constellation of Pegasus.
With an average apparent visual magnitude of 2.4, this is a second-magnit ...
,
Alpha Aquarii
Alpha Aquarii, officially named Sadalmelik (), is a single star in the constellation of Aquarius. The apparent visual magnitude of 2.94 makes this the second-brightest star in Aquarius. Based upon parallax measurements made during ...
,
Beta Aquarii
Beta Aquarii is a single star in the constellation of Aquarius. It has the official name Sadalsuud (), and sometimes is identified as β Aquarii, abbreviated Beta Aqr or β Aqr. Based upon parallax measurements obtained during the Hipparc ...
and
Delta Capricorni
Delta Capricorni, or δ Capricorni, is a binary star located 38,7 light-years from the Sun in the constellation of Capricornus (the Sea Goat). The system consists of an eclipsing binary, Delta Capricorni A, and two visual companions tha ...
.
Telescopic asterisms
![NGC 2169](https://upload.wikimedia.org/wikipedia/commons/9/95/NGC_2169.jpg)
Asterisms range from the large and obvious to the small, and even telescopic.
* The ''37'' or ''LE'' of
NGC 2169, in
Orion.
* The ''Engagement Ring'' in
Ursa Minor
Ursa Minor (Latin: 'Lesser Bear', contrasting with Ursa Major), also known as the Little Bear, is a constellation located in the far northern sky. As with the Great Bear, the tail of the Little Bear may also be seen as the handle of a ladle, ...
has the north star
Polaris as the diamond, at one end of a ring of much fainter stars about one degree across.
* The ''Broken Engagement Ring'' in
Ursa Major
Ursa Major (; also known as the Great Bear) is a constellation in the northern sky, whose associated mythology likely dates back into prehistory. Its Latin name means "greater (or larger) bear," referring to and contrasting it with nearby Ursa ...
at 10:51 / +56°10' (preceding β Ursae Majoris, Merak).
* The ''Christmas Tree'' shape of the
Christmas Tree Cluster
NGC 2264 is the designation number of the New General Catalogue that identifies two astronomical objects as a single object: the Cone Nebula, and the Christmas Tree Cluster. Two other objects are within this designation but not officially incl ...
, in
Monoceros
Monoceros (Greek: Μονόκερως, "unicorn") is a faint constellation on the celestial equator. Its definition is attributed to the 17th-century Dutch cartographer Petrus Plancius. It is bordered by Orion to the west, Gemini to the north, ...
. It is made up of about approximately 40 stars.
* ''
The Coathanger'', in
Vulpecula
Vulpecula is a faint constellation in the northern sky. Its name is Latin for "little fox", although it is commonly known simply as the fox. It was identified in the seventeenth century, and is located in the middle of the Summer Triangle (an ...
, also known as ''Brocchi's Cluster'' (see image at top).
* ''
Kemble's Cascade'', a chain of stars that ends in open cluster
NGC 1502
NGC 1502 is a young open cluster of approximately 60 stars in the constellation Camelopardalis, discovered by William Herschel on November 3, 1787. It has a visual magnitude of 6.0 and thus is dimly visible to the naked eye. This cluster is loc ...
, in
Camelopardalis.
* ''Napoleon's Hat'' (Picot 1), in
Bootes (south of α Bootis, Arcturus).
* ''The Ring of the Nibelungen'' (Ferrero 27) in
Draco
Draco is the Latin word for serpent or dragon.
Draco or Drako may also refer to:
People
* Draco (lawgiver) (from Greek: Δράκων; 7th century BC), the first lawgiver of ancient Athens, Greece, from whom the term ''draconian'' is derived
* ...
, named after the 1857
German epic drama, at 15:57 / +62°32' (near galaxy NGC 6015).
* The V-shaped
Messier 73 in
Aquarius
Aquarius may refer to:
Astrology
* Aquarius (astrology), an astrological sign
* Age of Aquarius, a time period in the cycle of astrological ages
Astronomy
* Aquarius (constellation)
* Aquarius in Chinese astronomy
Arts and entertainme ...
, determined to be an asterism in 2002.
[
]
See also
*
Australian Aboriginal astronomy
Australian Aboriginal astronomy is a name given to Aboriginal Australian culture relating to astronomical subjects – such as the Sun and Moon, the stars, planets, and the Milky Way, and their motions on the sky.
Traditional Aboriginal ...
*
Chinese constellation
Traditional Chinese astronomy has a system of dividing the celestial sphere into asterisms or constellations, known as "officials" ( Chinese ''xīng guān'').
The Chinese asterisms are generally smaller than the constellations of Hellenisti ...
*
Nakshatra
References
Bibliography
*
Allen, Richard Hinckley (1969). ''
Star Names: Their Lore and Meaning.'' Dover Publications Inc. (Reprint of 1899 original). .
*
Burnham, Robert (1978). ''Burnham's Celestial Handbook'' (3 vols). Dover Publications Inc. .
* Pasachoff, Jay M. (2000). ''A Field Guide to the Stars and Planets (4th ed.).'' Houghton Mifflin Co.
External links
List of Asterismsfrom deep-sky.co.uk
Discussion of AsterismsList of Asterismsfrom deepsky.waarnemen.com
List of Asterismsfrom nightskyatlas.com
from saguaroastro.org
from waynesthisandthat.com
{{DEFAULTSORT:Asterism (Astronomy)
Stellar groupings
+
Former constellations