constellations

Because the human brain has a powerful urge to recognize pattern, we see patterns in the night sky, patterns like the Big Dipper. These patterns are called “asterisms.” Most asterisms are due to our point of view, and are not the result of a real, physical grouping of stars. An asterism may include small nearby stars and giant but distant ones.

Names of the constellations

Many cultures have had named constellations: the Chinese, for example. But because modern astronomy arose out of the Western tradition, the names now used internationally have Western roots. A number of constellations are mentioned in Homer (9th century bce), and Greek references are frequent by the 6th century bce, but the names appear to have come from even older cultures along the Euphrates River, possibly by way of the Phoenicians.

Drawing on the work of the astronomer Eudoxus, sometime around 270 bce a poet named Aratus wrote a long poem called Phenomena, in which he described 44 constellations and told their stories. This work was extremely popular in classical times. No less an author than Cicero translated it into Latin. To this day, most books that tell the stories of the constellations are retellings of Aratus.

Ptolemy listed 48 constellations and their locations in his He Mathematike Syntaxis (2nd century ad). Medieval Europeans knew this work as the Almagest, its translation into Arabic. Most of the constellation names given in the Almagest are still in use.

Astronomers' view of constellations

To the astronomer, a constellation is not an asterism, but a well-defined area on the celestial sphere. So, for example, every constellation that is a part of the zodiac must occupy exactly one-twelfth of the celestial equator, a point recognized by the ancient Greeks. Every point on the celestial sphere must lie in one constellation or another; the entire celestial sphere is tiled with constellations.

As European astronomers began to travel to the Southern Hemisphere, more names were required to cover the part of the celestial sphere that can never be seen from Earth's Northern Hemisphere. The names of twelve of these southern constellations, suggested by Pieter Dirckszoon Keyzer, Amerigo Vespucci, Andrea Corsali and Pedro de Medina, were canonized by their use in 1630 in plate 49 of Johnn Bayer's extremely popular star atlas, Uranometria. By the end of the 17th century, astronomers were inventing new constellations to fill those regions which, because they contained few prominent stars, had never been identified with a particular constellation.

Boundary of the constellation Orion.

Differing definitions of the constellations and the use of curved boundaries (which made it a bit more difficult to determine in which constellation a given location lay) led the International Astronomical Union to standardize the names and the boundaries of the constellations in 1930, making them all run either north-south or east-west, like lines of latitude and longitude on the Earth.²

The names of the constellations are used in naming prominent stars; in a star's name the genitive form of the constellation's name is used, or it is abbreviated. The redrawing of the constellations' boundaries in 1930 resulted in a few stars no longer being in the constellations from which they take their names.

The system of three letter abbreviations for the names of constellations was proposed by Hertzsprung and Russell, and adopted with slight modifications by the First General Assembly of the IAU in 1922.¹At the same meeting, it was decided that astronomers would use only the Latin form of the names of constellations.

The genitive form and abbreviation are given in the table below. The size is given in square degrees.² In comments, the letter refers to the first record of the name:

P = mentioned in Ptolemy, Almagest (2nd century ad);
B = Johann Bayer, Uranometria (1603)
H = Johann Hewelke (1611–1687, Latin, Johannes Hevelius) of Danzig in his posthumously published celestial atlases, Firmamentum sobiescanium and Prodromus Astronomiae (1690).
L = Nicholas Louis de Lacaille, Caelum Australe Stelliferum (1763)

Name	Genitive	Abbr.	Meaning of name	Size sq. °	Comment
Andromeda	Andromedae	And	an Ethiopian princess	722	P
Antlia	Antilae	Ant	air pump	239	L, originally Antilia Pneumatica
Apus	Apodis	Aps	bird of paradise	206	B, originally Avis Indica
Aquarius	Aquarii	Aqr	water bearer	980	P
Aquila	Aquilae	Aql	eagle	653	P
Ara	Arae	Ara	altar	237	P
Aries	Arietis	Ari	ram	441	P
Auriga	Aurigae	Aur	charioteer	657	P
Boötes	Bootis	Boo	herdsman	907	P
Caelum	Caeli	Cae	chisel	125	L, originally Caela Sculptoris
Camelopardalis	Camelopardalis	Cam	giraffe	757	H
Cancer	Cancri	Cnc	crab	506	P
Canes Venatici	Canum Venaticorum	CVn	hunting dogs	465	H
Canis Major	Canis Majoris	CMa	big dog	389	P
Canis Minor	Canis Minoris	CMi	small dog	183	P
Capricornus	Capricorni	Cap	goat	414	P
Carina	Carinae	Car	ship's keel	494	formerly part of Argo Navis
Cassiopeia	Cassiopeiae	Cas	an Ethiopian queen	598	P
Centaurus	Centauri	Cen	centaur	1,060	P
Cepheus	Cephei	Cep	king of Ethiopia	588	P
Cetus	Ceti	Cet	whale	1,231	P
Chamaeleon	Chamaeleonis	Cha	chameleon	132	B
Circinus	Circini	Cir	compass	93	L
Columba	Columbae	Col	dove	270	Jacobus Bartschius, 1694, as Columba Noachi (Noah's Dove)
Coma Berenices	Comae Berenices	Com	Bernice's hair	387	3rd century bce, but not recorded until Tycho Brahe's catalog (1602)
Corona Austrina	Coronae Austrinae	CrA	southern crown	128	P. Sometimes called Corona Australis
Corona Borealis	Coronae Borealis	CrB	northern crown	179	P
Corvus	Corvi	Crv	crow	184	P
Crater	Crateris	Crt	cup	282	P
Crux	Crucis	Cru	cross	68	Augustine Royer, 1679) as Crux Australis, the Southern Cross.
Cygnus	Cygni	Cyg	swan	804	P
Delphinus	Delphini	Del	porpoise	189	P
Dorado	Doradus	Dor	swordfish	179	B
Draco	Draconis	Dra	dragon	1083	P
Equuleus	Equulei	Equ	little horse	72	P
Eridanus	Eridani	Eri	the River Eridanus	1,138	P
Fornax	Fornacis	For	furnace	398	L, originally Fornax Chemica
Gemini	Geminorum	Gem	twins	514	P
Grus	Gruis	Gru	crane	366	B
Hercules	Herculis	Her	Hercules	1,225	P
Horologium	Horologii	Hor	clock	249	L
Hydra	Hydrae	Hya	the Hydra	1,303	P
Hydrus	Hydri	Hyi	male water snake	243	B
Indus	Indi	Ind	Indian	294	B
Lacerta	Lacertae	Lac	lizard	201	H
Leo	Leonis	Leo	lion	947	P
Leo Minor	Leonis Minoris	Lmi	little lion	232	H
Lepus	Leporis	Lep	hare	290	P
Libra	Librae	Lib	balance	538	P
Lupus	Lupi	Lup	wolf	334	P
Lynx	Lyncis	Lyn	lynx	545	H
Lyra	Lyrae	Lyr	lyre	286	P
Mensa	Mensae	Men	table	154	L, originally Mons Mensae
Microscopium	Microscopii	Mic	microscope	210	L
Monoceros	Monocerotis	Mon	unicorn	482	H
Musca	Muscae	Mus	fly	138	B. Originally also called Apis.
Norma	Normae	Nor	square or level	165	L, originally Quadra Euclidis
Octans	Octantis	Oct	octant	291	L
Ophiuchus	Ophiuchi	Oph	Ophiuchus, the serpant-bearer	948	P
Orion	Orionis	Ori	Orion, hunter	594	P
Pavo	Pavonis	Pav	peacock	378	B
Pegasus	Pegasi	Peg	Pegasus, the winged horse	1,121	P
Perseus	Persei	Per	Perseus, rescuer of Andromeda	615	P
Phoenix	Phoenicis	Phe	the phoenix	469	B
Pictor	Pictoris	Pic	painter or easel	247	L, originally Equuleus Pictoris
Pisces	Piscium	Psc	fish	889	P
Piscis Austrinus	Piscis Austrini	PsA	southern fish	245
Puppis	Puppis	Pup	ship's stern	673	formerly part of Argo Navis
Pyxis	Pyxidis	Pyx	ship's compass, previously part of Argo Navis	221	L, originally Pyxis Nautica
Reticulum	Reticuli	Ret	net	114	L, originally Reticulus Rhomboidalis
Sagitta	Sagittae	Sge	arrow	80	P
Sagittarius	Sagittarii	Sge	archer	867	P
Scorpius	Scorpii	Sco	scorpion	497	P
Sculptor	Sculptoris	Scl	sculptor	475	L, originally Apparatus Sculptoris
Scutum	Scuti	Sct	shield	109	H, originally Scutum Sobieskii
Serpens Sometimes divided into Serpens Caput and Serpens Cauda	Serpentis	Ser	serpent	637	P
Sextans	Sextantis	Sex	sextant	314	H, originally Sextans Uraniae
Taurus	Tauri	Tau	bull	797	P
Telescopium	Telescopii	Tel	telescope	252	L
Triangulum	Trianguli	Tri	triangle	132	P
Triangulum Australe	Trianguli Australis	TrA	southern triangle	110	B
Tucana	Tucanae	Tuc	toucan	295	B
Ursa Major	Ursae Majoris	UMa	big bear	1,280	P
Ursa Minor	Ursae Minoris	UMi	little bear	256	P
Vela	Velorum	Vel	ship's sail	500	formerly part of Argo Navis
Virgo	Virginis	Vir	virgin	1,294	P
Volans	Volantis	Vol	flying fish	141	B, originally Piscis Volans
Vulpecula	Vulpeculae	Vul	little fox	268	H, originally Vulpecula et Anser (fox and goose)

1. A. Fowler, ed.
First General Assembly, held at Rome, May 2nd to May 10th, 1922.
Transactions of the International Astronomical Union. Volume 1.
London: Imperial College Bookstall, no date [1922 ?].

Pages 23, 158, 207. See also Transactions of the IAU, volume 4, page 221; volume 9, pages 66 and 77.

2. E. Delaporte.
Delimitation scientifique des constellations (tables et cartes).
Cambridge (UK): Cambridge University Press, 1930.

See also:
A. Levin.
Areas of the constellations.
British Astronomical Association Handbook (1935)

3. Aratus, in Callimachus, Hymns and Fragments; Lycophron; Aratus.
G. R. Mair, translator.
Loeb Classical Library.
London: William Heinemann; New York: G. P. Putnams. (1921)

Douglas Kidd.
Aratus. Phaenomena.
Cambridge: Cambridge University Press, 1997.

Very expensive scholarly book.

For Further Reading

	Michael E. Bakich. Cambridge Guide to the Constellations. Cambridge University Press, 1995. Wonderful.
	Theony Condos. Star Myths of the Greeks and Romans: A Sourcebook Containing the Constellations of Pseudo-Eratosthenes and the Poetic Astronomy of Hyginus. Phanes Press, 1997. Sources in the Western tradition, for scholars.
	Jacqueline Mitton. Once Upon a Starry Night. National Geographic Society, 2004. or, by the same author, Zoo in the Sky. National Geographic Society, 1998.
	H. A. Rey Find the Constellations. Houghton Mifflin, 1954. Several revised editions, most recent edition in 1988. Classic children's book, by the author of the Curious George books. It has stood the test of time and is just as useful to adults wishing to learn the constellations.
	Julius D. W. Staal. The New Patterns in the Sky. Myths and Legends of the Stars. McDonald and Woodward, 1996. (Revision of a 1988 edition) Recommended as an introduction at middle school and above.