Located in the southern sky, Centaurus is a bright constellation that is one of the largest constellations. Centaurus was included among the 48 constellations listed by the 2nd-century astronomer Ptolemy, and remains one of the 88 modern constellations. Centaurus belongs to the Hercules family of constellations.

In Greek mythology, Centaurus represents a centaur, which is a creature that is half human, half horse. Notable stars in the constellation include Alpha Centauri, the nearest star system to the Solar System, and V766 Centauri which is one of the largest stars discovered so far. The brightest globular cluster is Omega Centauri, is visible from Earth and the largest identified in the Milky Way.

The stars Alpha and Beta Centauri, also known as Rigil Kentaurus and Hadar, serve as pointers to the Southern Cross, which lies under the centaur’s rear legs.

While Centaurus now has a high southern latitude, at the dawn of civilization it was an equatorial constellation. In a little over 7000 years it will be at maximum visibility for those in the northern hemisphere.

	Applicable Information
Visibility In Pacific Northwest	January to July
Best Times To View	May
Right Ascension	11h 05m 20.9415s–15h 03m 11.1071s
Declination	−29.9948788°–−64.6957885°
Area	1060 square degrees
Main Stars	11
Brightest Object	α Cen
Meteor showers	Alpha Centaurids, Omicron Centaurids, Theta Centaurids
Messier objects	0
Neighboring Constellations	Antlia, Carina, Circinus, Crux, Hydra, Libra, Lupus, Musca, Vela

Historical Context

The figure of Centaurus can be traced back to a Babylonian constellation known as the Bison-man, which had several forms. The Babylonians closely associated the constellation with the Sun god Utu-Shamash from very early times.

The Greeks depicted the constellation as a centaur and gave it its current name, which was mentioned by Eudoxus in the 4th century BC and Aratus in the 3rd century BC. As the constellation Lupus was treated as an asterism within Centaurus, the constellation used to be larger than it is now.

The Southern Cross, which is now regarded as a separate constellation, was treated by the ancients as a mere asterism formed of the stars composing the centaur’s legs. Moreover, the minor constellation Circinus was treated as undefined stars under the centaur’s front hooves.

In Chinese astronomy, the stars of Centaurus are found in the three areas of the Azure Dragon of the East, the Vermillion Bird of the South, and the Southern Asterisms. Although not all of the stars of Centaurus can be seen from China; most of the brightest stars of Centaurus can be seen in the Chinese sky.

Some Polynesian peoples considered the stars of Centaurus to be a constellation as well.

Bugis sailors use the asterism of the Pointer, which includes the stars α Centauri and β Centauri for navigation. Names for this asterism include bintoéng balué, meaning “the widowed-before-marriage”and bintoéng sallatang meaning “southern star” 

Ovid the Roman poet says that the constellation honors the centaur Chiron, who was tutor to many of the earlier Greek heroes including Heracles, Theseus, and Jason, the leader of the Argonauts.

Stars

Centaurus contains several very bright stars, and its alpha and beta stars are used as “pointer stars” to help observers find the constellation Crux. Centaurus has 281 stars above magnitude 6.5 that are visible to the unaided eye, which is the greatest amount of any constellation.

ω Centauri, otherwise known as NGC 5139, is a naked eye visible globular cluster, despite being listed as the constellation’s “omega” star. It is the largest and brightest globular cluster in the Milky Way; at ten times the size of the next-largest cluster, also being the most luminous globular cluster in the Milky Way, at over one million solar luminosities.

Centaurus is also home to open clusters. NGC 3766 is an open cluster visible to the unaided eye that contains approximately 100 stars.

Visible by the naked eye, open cluster NGC 5460 has an overall magnitude of 6 and contains approximately 40 stars.

There is 1 bright planetary nebula in Centaurus, which is NGC 3918, otherwise known as the Blue Planetary. Discovered by John Herschel, the Blue Planetary is named for its color’s similarity to Uranus.

Centaurus is rich in galaxies. NGC 4622 is a face-on spiral galaxy with spiral arms winding in both directions, which makes it nearly impossible for astronomers to determine the rotation of the galaxy.

NGC 4945 is a spiral galaxy seen edge-on from Earth, which is visible with any amateur telescope, as well as binoculars under good conditions. Another galaxy visible to amateur telescopes is NGC 5102, which can be found by star-hopping from Iota Centauri.

One of the closest active galaxies to Earth is the Centaurus A galaxy, NGC 5128, which has a supermassive black hole at its core. It expels massive jets of matter that emit radio waves due to synchrotron radiation. NGC 5128 appears in the optical spectrum as a fairly large elliptical galaxy with a prominent dust lane. It can be seen by the naked eye under perfect conditions and is easily found by star hopping from Omega Centauri. In small telescopes, the dust lane is not visible; it begins to appear with about 4 inches of aperture under good conditions. In large amateur instruments, above about 12 inches in aperture, the dust lane’s west-northwest to east-southeast direction is easily discerned.

NGC 4650A is a polar-ring galaxy that has a central core made of older stars that resembles an elliptical galaxy, and an outer ring of young stars that orbits around the core. The plane of the outer ring is distorted, which suggests that NGC 4650A is the result of a galaxy collision about a billion years ago.

One of the closest galaxy clusters to Earth is the Centaurus Cluster, which has an intracluster medium with a high concentration of metals heavier than helium. The number of heavy metals due to to a large number of supernovae.

Make sure to check out other articles on the site, including a brief introduction to constellations, other constellation articles, and more!