Corona Australis
“The Southern Crown” · Southern · best around August evenings
Real star positions and magnitudes (HYG database via D3-Celestial, BSD-3). Lines are the conventional stick figure; north is up.
The story
A graceful little arc of stars beneath Sagittarius — the wreath fallen from the archer's head. Ancient, despite its faintness.
How to find it
The curl of stars just south of the Teapot.
✦ What lives inside it
- A nearby star-forming dust cloud
The deep dive
Researched for the Atlas from Wikipedia — Corona Australis (16,769 characters read) · updated Sep 20, 2026
01 A crown with an identity crisis
Corona Australis has never quite settled on what it is. The ancient Greeks did not call it a crown at all — Aratus, writing in the 3rd century BC, referred to both crowns together simply as Stephanoi, meaning wreaths, without giving this southern one a name of its own. Ptolemy, writing in the 2nd century AD, named it Stephanos notios, the "Southern Wreath," and catalogued 13 stars in it, though one of those — Alpha Telescopii — was later transferred to the neighbouring constellation Telescopium. Roman writers called it the "Golden Crown of Sagittarius," while in the 5th century it was known as Parvum Coelum, meaning "Canopy" or "Little Sky." The 18th-century French astronomer Jérôme Lalande contributed two more names: Sertum Australe, "Southern Garland," and Orbiculus Capitis. German poet Philippus Caesius preferred Corolla, "Little Crown," or Spira Australis, "Southern Coil," and connected it to the Crown of Eternal Life from the New Testament. The 17th-century cartographer Julius Schiller linked it instead to the Diadem of Solomon. Few constellations have collected quite so many competing identities.
02 Alpha CrA: the one star with a proper name
Of all the stars in Corona Australis, only one has been granted an official proper name by the International Astronomical Union: Alpha Coronae Australis, known as Alfecca Meridiana or simply Meridiana. The name fuses two traditions — Alfecca comes from the Arabic word for "break," describing the open shape shared by both Corona Australis and Corona Borealis, while Meridiana is Latin for "southern." The star itself is a white main-sequence star of spectral type A2Va sitting 125 light years from Earth, with an apparent magnitude of 4.10. What makes it physically interesting is its rotation: it spins at almost 200 km per second at its equator, completing a full revolution in roughly 14 hours. For comparison, the Sun takes about 25 days to rotate once. Like the star Vega, Alfecca Meridiana shows excess infrared radiation, hinting at a surrounding disk of dust. It is 31 times more luminous than the Sun and has 2.3 times the Sun's radius and mass. Eventually, though it is currently on the main sequence, it will evolve into a white dwarf.
03 Beta CrA: a well-evolved giant Deeper
Beta Coronae Australis offers a fascinating contrast to its near-twin in brightness. Though both Alpha and Beta share apparent magnitudes close enough — 4.10 and 4.11 respectively — that the naked eye cannot distinguish them, they are physically worlds apart. Beta is an orange giant of spectral type K0II, classed as a bright giant, lying 474 light years away — nearly four times the distance of Alpha. Its history is written in its spectrum: it began life as a hot B-type star and has since evolved all the way to a cool K-type giant, a journey that took roughly 100 million years. Today it has a radius of 43 solar radii — so large that if placed at the Sun's position it would extend well past Mercury's orbit — and a mass of between 4.5 and 5 solar masses. Its luminosity is 730 times that of the Sun, placing it among the most luminous K0-type stars visible to the unaided eye anywhere in the sky. Beta Coronae Australis is a reminder that two stars can look identical from Earth while existing in completely different stages of stellar life.
04 Double stars for every aperture size
Corona Australis is a surprisingly productive field for double-star observers across a range of telescope sizes. Gamma Coronae Australis is a genuine binary system — two F8V dwarf stars, each of magnitude 5.01, that orbit each other every 122 years. They lie 58 light years away, separated by just 1.3 arcseconds at a position angle of 61 degrees, so a 100 mm aperture is enough to split them; they have been widening since 1990. Lambda Coronae Australis, 202 light years distant, is more forgiving: its A2Vn primary of magnitude 5.1 and its magnitude 9.7 companion are separated by 29.2 arcseconds at an angle of 214 degrees, resolvable in small telescopes. Kappa Coronae Australis is a purely optical double — two unrelated stars that happen to share the same line of sight, one roughly 150 light years away and the other about 1000 light years. Separated by 21.6 arcseconds, the dimmer-looking Kappa1 (spectral type A0III) is actually the more distant, while the bluer Kappa2 (spectral type B9V, apparent magnitude 5.6) is the brighter of the pair despite appearing so. Eta1 and Eta2 CrA form another optical double, separable with the naked eye at magnitudes 5.1 and 5.5.
05 Epsilon CrA: the south's top contact binary Deeper
Epsilon Coronae Australis holds a distinctive record: it is the brightest example of a W Ursae Majoris variable in the entire southern sky. W Ursae Majoris systems are a class of eclipsing binary called contact binaries, meaning the two component stars are so gravitationally close that they literally touch and share an outer envelope of gas. In the case of Epsilon CrA, the system sits 98 light years away and carries the spectral designation F4VFe-0.8+, the unusual notation reflecting an underabundance of iron in its atmosphere. The system's combined brightness hovers around an average apparent magnitude of 4.83 but dips and rises by about a quarter of a magnitude as the two stars eclipse each other — completing one full cycle every seven hours. That rapid period gives observers a chance to watch measurable brightness changes within the span of a single evening's session. Contact binaries are scientifically valuable because the physics of two stars sharing material across their mutual surface is still not fully understood, making bright, accessible examples like Epsilon CrA useful benchmarks.
06 A neutron star hiding in the crown Deeper
Tucked inside Corona Australis is one of the most intriguing stellar remnants known: RX J1856.5-3754, an isolated neutron star. Neutron stars are the collapsed cores of massive stars that exploded as supernovae, compressing roughly a solar mass of material into an object with a diameter of only about 14 km — roughly the width of a city. The article gives its distance as 140 parsecs, with an uncertainty of ±40 parsecs (approximately 460 ±130 light years). RX J1856.5-3754 attracted significant scientific controversy because for a time astronomers suspected it might be a strange star — an even more exotic object theorised to be composed of strange quarks rather than neutrons. That hypothesis has since been discounted. The object is described as isolated, meaning it does not have a visible companion star and is not currently accreting material, making it a relatively clean object for studying the extreme physics of ultradense matter. Its presence in a relatively nearby constellation like Corona Australis makes it one of the closer known neutron stars to the Solar System.
07 Mythologies from four continents
No constellation on the sky carries richer cross-cultural freight than Corona Australis. In ancient Mesopotamia it may appear in the MUL.APIN star catalogue as MA.GUR, "The Bark" (a type of boat), listed among the fifteen "stars of Ea" — though scholars note the identification is uncertain, as the same stars may instead represent Epsilon Sagittarii. Roman mythology tied it to Bacchus: Jupiter fathered Bacchus on the mortal Stimula; the jealous Juno tricked Stimula into asking Jupiter to reveal his full divine glory, which killed her. When Bacchus grew up to become god of wine he placed a wreath in the sky to honour his mother. In South Africa, the ǀXam-speaking San people saw "a house of branches" owned by the rock hyrax, with the stars depicting people sitting in a semicircle around a fire. In northwestern Victoria, the Boorong people identified it as Won, a boomerang thrown by Totyarguil (the star Altair). The Aranda people of Central Australia saw it as a coolamon — a carrying dish — dropped by sky-women dancing in the Milky Way; their tradition holds that its impact formed Gosses Bluff crater, 175 km west of Alice Springs. On Futuna island it was called Tanuma, and in the Tuamotu archipelago it was called Na Kaua-ki-Tonga.
08 Torres Strait Islanders and Tagai's canoe
The Torres Strait Islanders incorporated Corona Australis into an expansive asterism far larger than any Western constellation, one stretching across parts of Sagittarius and the tip of Scorpius's tail and drawing in the Pleiades and Orion as well. The whole figure was understood as the canoe of Tagai, a heroic figure, crewed by the Pleiades — called the Usiam — and Orion, called the Seg. Within the story, Tagai discovered his crewmen had consumed all of the canoe's supplies without permission. Enraged, he bound the Usiam with rope, tied them to the side of the boat, and threw them overboard. Scorpius's tail represents a suckerfish in this tradition, while specific stars mark the structural parts of the vessel: Eta Sagittarii and Theta Coronae Australis indicate the bottom of the canoe. This tradition illustrates how Indigenous astronomical knowledge often integrated multiple Western constellations into a single coherent and morally instructive narrative, encoding seasonal information, navigation, and social values simultaneously in the same star pattern.
09 Chinese astronomy and the Heavenly Turtle
In the Chinese astronomical tradition, the stars of Corona Australis fall within the mansion of the Black Tortoise of the North (北方玄武, Běi Fāng Xuán Wǔ), one of the four great symbolic animals dividing the sky. The constellation itself was called ti'en pieh, meaning "Heavenly Turtle." During the Western Zhou period — roughly 1046 to 771 BC — the Heavenly Turtle served as a calendar marker, signalling the beginning of winter when it appeared in the appropriate position. Over centuries, however, the slow wobble of Earth's axis known as precession shifted the stars' relationship to the seasons. As a result, the Milky Way — referred to in Chinese tradition as the "Heavenly River" — became a more reliable seasonal indicator than the Heavenly Turtle and gradually supplanted it in that role. Meanwhile, Arabic astronomers knew the same star pattern under multiple names: Al Ķubbah, "the Tortoise"; Al Ĥibā, "the Tent"; and Al Udḥā al Na'ām, "the Ostrich Nest." Later the Arabic name Al Iklīl al Janūbiyyah was adopted, which European authors transliterated in various ways — Alachil Elgenubi, Elkleil Elgenubi, and Aladil Algenubi — as they imported Arabic astronomical knowledge into Latin scholarship.
10 The Corona Australids: a shower of surprises
Corona Australis gives its name to a minor but intriguing meteor shower, the Corona Australids, which runs from 14 to 18 March each year and peaks around 16 March. With a duration of only six days it is particularly short-lived, and its meteoroids are consistently small — the stream is described as devoid of large meteoroids. Typical peak rates are modest: observers recorded maximums of 6 meteors per hour in 1953 and just 4 per hour in 1956, and in 1955 the shower was "barely resolved" at all. Yet in 1992 astronomers detected a peak rate of 45 meteors per hour, demonstrating that year-to-year variation can be dramatic. The shower was first seen with the unaided eye in 1935 and first tracked by radar in 1955. Corona Australid meteors enter the atmosphere at 45 kilometres per second. A separate, younger-designated shower — the Beta Coronae Australids — was formally identified in 2006, originating near Beta Coronae Australis and appearing in May. Although it shares the sky that month with the nearby May Microscopids shower, the two have distinct trajectories and are considered unrelated.
11 NGC 6541: an ancient globular at the edge of sight
Halfway between Theta Coronae Australis and Theta Scorpii lies NGC 6541, a dense globular cluster that rewards observers using nothing more than binoculars or a small telescope. Its brightness has been reported as between magnitude 6.3 and 6.6 — the small range reflecting the difficulty of measuring extended objects precisely. At an estimated distance of around 22,000 light years, its apparent diameter of 13.1 arcminutes corresponds to a true diameter of roughly 100 light years. Its age is estimated at around 14 billion years, making it one of the oldest objects in the Milky Way, formed when the universe itself was still very young. Larger amateur instruments begin to resolve individual stars within it — a 12-inch telescope reveals approximately 100 stars — but the cluster's core remains unresolved even then, a sign of just how tightly packed the central stars are. NGC 6541 sits in a region of sky close enough to the Milky Way's crowded star fields to create a visually rich surrounding field, making it a satisfying target even for casual observers.
12 IC 1297 and the merging galaxies of CrA Deeper
Despite its small area and low galactic latitude — which crowds the field with foreground stars and obscuring dust — Corona Australis does host a handful of deep-sky objects beyond its famous molecular cloud. IC 1297 is a compact planetary nebula of apparent magnitude 10.7, only 7 arcseconds in diameter, making it a challenging but rewarding target for higher-powered amateur instruments. It has been described in the eyepiece as "a square with rounded edges," elongated in the north-south direction, and its colour has been reported variously as blue, blue-tinged green, and green-tinged blue — a disagreement that likely reflects both the object's true spectral complexity and differences between observers' eyes. At its centre sits the variable star RU Coronae Australis, a Wolf-Rayet star of WC class with an average apparent magnitude of 12.9. Nearby, NGC 6768 is a magnitude 11.2 object just 35 arcminutes south of IC 1297, and it is physically unusual: it consists of two galaxies in the process of merging, one an elongated elliptical classified E4 and the other a lenticular galaxy classified S0. The near-Milky-Way location means galaxies are uncommon finds in this constellation, making this merging pair a notable exception.
13 The IAU name debate that lasted 33 years Deeper
Even the official name of Corona Australis has a complicated administrative history. When the International Astronomical Union standardised the 88 modern constellations in 1922, it entered the name as "Corona Australis." Ten years later, in 1932, the IAU's commission on notation approved a list of four-letter abbreviations for all constellations and at that point recorded the name instead as "Corona Austrina" — a subtly different Latin form. The four-letter abbreviation system proved impractical and was repealed in 1955, at which point "Corona Australis" was restored as the sole official name, where it has remained ever since. The three-letter abbreviation CrA, adopted in 1922, was never in dispute. The constellation's borders were formalised separately by Belgian astronomer Eugène Delporte in 1930, defined by a polygon of four segments in the equatorial coordinate system, with right ascension running from 17h 58.3m to 19h 19.0m and declination from −36.77° to −45.52°. Covering 128 square degrees, it ranks 80th among the 88 constellations in area — firmly in the smaller half of the sky's official figures.