Grus
“The Crane” · Southern · best around October evenings
Real star positions and magnitudes (HYG database via D3-Celestial, BSD-3). Lines are the conventional stick figure; north is up.
The story
The long-necked crane of the southern spring sky, from the 1590s Dutch charts — graceful and reasonably bright, below Fomalhaut.
How to find it
South of Fomalhaut on spring (southern) evenings.
✦ What lives inside it
- The Grus Quartet of interacting galaxies
The deep dive
Researched for the Atlas from Wikipedia — Grus (constellation) (13,195 characters read) · updated Sep 20, 2026
01 Born from a voyage to the East Indies
Grus owes its existence to a single Dutch trading expedition. When Pieter Dirkszoon Keyser and Frederick de Houtman sailed on the Eerste Schipvaart — the first Dutch voyage to the East Indies — they systematically catalogued the southern sky in a way European astronomy had never managed before. Their observations were handed to Petrus Plancius, who used them to carve out twelve new constellations. Grus made its public debut on a 35-centimetre-diameter celestial globe published in 1598 in Amsterdam by Plancius and cartographer Jodocus Hondius, and five years later it appeared in Johann Bayer's landmark star atlas Uranometria of 1603. De Houtman himself listed the stars in his southern catalogue the same year, but under the Dutch name Den Reygher, meaning "The Heron" — a subtle difference that Bayer ignored, preferring the Latin Grus, meaning crane. That choice stuck, and the heron name quietly disappeared from the record.
02 When Grus was briefly a flamingo
For a short window in the early seventeenth century, the constellation almost became a flamingo rather than a crane. The alternative Latin name Phoenicopterus — literally "flamingo" — appears in Paul Merula's 1605 work Cosmographiae Generalis, published out of Leiden University, and again on a globe made around 1625 by Dutch globe maker Pieter van den Keere. Astronomer Ian Ridpath has traced the symbolism back to Plancius himself, who had professional connections with both Merula and van den Keere. The flamingo identity never gained lasting traction, however, and by the time constellation boundaries were formally standardised, Grus the crane had completely won out. The episode is a small reminder that the southern constellations we take for granted today were anything but settled at birth — they were products of individual decisions, personal networks, and commercial globe-making, not any single authoritative decree.
03 Alnair: the bright one that wasn't always a crane's star
Alpha Gruis carries the traditional name Alnair, derived from an Arabic phrase meaning "the bright one." The name predates Grus as a constellation, because Arab astronomers knew this star not as part of a crane but as the brightest point in the tail of Piscis Austrinus, the southern fish. When Plancius separated Grus from its northern neighbour, Alnair came with it. The star itself is a blue-white main-sequence object of spectral type B6V sitting about 101 light-years from Earth, shining at apparent magnitude 1.7. Despite looking modest compared to the very brightest stars in the sky, Alnair is physically impressive: it is roughly 380 times as luminous as the Sun and has more than three times the Sun's diameter. Nicolas-Louis de Lacaille formally assigned it the Alpha designation in 1756, cementing its status as the constellation's leading light.
04 Beta Gruis: a giant star reaching toward Venus Deeper
Beta Gruis, whose proper name is Tiaki, presents a striking physical picture. It is a red giant of spectral type M5III, situated about 170 light-years from Earth and lying roughly 5 degrees west of Alnair. Its diameter measures 0.8 astronomical units — meaning that if Tiaki were dropped into the centre of the Solar System in place of the Sun, its surface would extend all the way out to the orbit of Venus. That single comparison captures how radically a star can swell in its red giant phase. Tiaki is also a variable star, fluctuating between apparent magnitude 2.0 at its brightest and 2.3 at its faintest, a subtle range but still noticeable to a careful naked-eye observer. Gamma Gruis, by contrast, marks the crane's eye in the northwest corner of the constellation: a blue-white subgiant of spectral type B8III at magnitude 3.0, lying about 211 light-years away, it has already exhausted its core hydrogen and is beginning the slow expansion that will eventually transform it into a red giant as well.
05 A sky full of optical doubles in one constellation Deeper
Grus is unusually rich in naked-eye optical double stars — pairs that appear close together in the sky but are unrelated stars sitting at very different distances. Delta Gruis splits into Delta1 and Delta2, separated by 45 arcseconds. Delta1 is a yellow giant 309 light-years away, while Delta2 is a semiregular red giant variable ranging between magnitudes 3.99 and 4.2, located 325 light-years away, with roughly three times the Sun's mass and 135 times its diameter. Mu Gruis is another optical double: both Mu1 and Mu2 are yellow giants of spectral type G8III, each about 2.5 times as massive as the Sun with surface temperatures near 4,900 K, separated only by about 10 light-years in space. Pi Gruis adds further variety — Pi1 is a semiregular S-class red giant varying from magnitude 5.31 to 7.01 over 191 days and sits about 532 light-years away, while the optically nearby Pi2 is a type F3III-IV giant only 130 light-years distant and often outshines its companion at magnitude 5.6.
06 Cataclysmic variables: white dwarfs feeding in Grus Deeper
Two unusual binary systems in Grus feature white dwarfs actively consuming material from companion stars. RZ Gruis is a binary of apparent magnitude 12.3, occasionally dimming to 13.4, in which a white dwarf and a main-sequence star are thought to orbit each other roughly every 8.5 to 10 hours. It belongs to the UX Ursae Majoris subgroup of cataclysmic variables, where the donor star feeds material into an accretion disc around the white dwarf; that disc glows so brightly it outshines both stars. The donor has been calculated to be of spectral type F5V, though the system remains poorly understood. Its spectra resemble novae returning to quiescence after outbursts, yet RZ Gruis has never itself been observed to erupt — a puzzle that led the American Association of Variable Star Observers to flag it for continued monitoring. CE Gruis takes matters further: here the white dwarf and donor are so close they are tidally locked. Material streams directly onto the white dwarf without forming a disc at all, making CE Gruis a member of the class known as polars.
07 A hypervelocity star flung from the galaxy's core
In July 2019, astronomers announced one of the most dramatic stellar discoveries in recent memory: a star designated S5-HVS1, located in Grus about 29,000 light-years from Earth, was found to be travelling at 1,755 kilometres per second — equivalent to roughly 3,930,000 miles per hour — faster than any other star detected up to that point. The leading explanation is that the star was propelled to such extreme speed after interacting with Sagittarius A*, the supermassive black hole at the centre of the Milky Way. In this scenario, S5-HVS1 was once part of a binary system that strayed too close to the galactic centre; the black hole's immense gravity captured one star of the pair and violently ejected the other at hypervelocity. The star may ultimately escape the Milky Way entirely. Its discovery inside the boundaries of what is otherwise a quiet southern constellation was entirely unexpected and underscores how much remains unknown about stellar dynamics near the galactic core.
08 The Spare Tyre Nebula and a quartet of colliding galaxies
Grus contains two deep-sky showpieces worth knowing by name. IC 5148, nicknamed the Spare Tyre Nebula, is a planetary nebula sitting about 1 degree west of Lambda Gruis, roughly 3,000 light-years away. What makes it remarkable is its speed: it is expanding at 50 kilometres per second, placing it among the fastest-expanding planetary nebulae known. Northeast of Theta Gruis lies the Grus Quartet, a group of four interacting galaxies — NGC 7552, NGC 7582, NGC 7590, and NGC 7599. The latter three are packed into a patch of sky only 10 arcminutes across and are sometimes called the Grus Triplet, though all four belong to the larger IC 1459 Grus Group. NGC 7552 and NGC 7582 are both blazing with starburst activity, a burst of accelerated star formation driven by the gravitational tidal forces the galaxies are exerting on one another as they interact — a vivid demonstration that galaxy collisions do not just destroy structure but can also trigger dramatic new episodes of creation.
09 IC 1459: a galaxy spinning against itself Deeper
On the border between Grus and Piscis Austrinus sits IC 1459, classified as a peculiar E3 giant elliptical galaxy with an apparent magnitude of 11.9. At roughly 80 million light-years distant, it is one of the more remote objects associated with the Grus region. What makes IC 1459 scientifically striking is its interior: the galaxy harbours a fast counterrotating stellar core, meaning that the stars at its centre are spinning in the opposite direction from the stars in its outer body. Its outer regions also show shells and ripples — faint structures that are widely interpreted as the debris signatures of a past merger or collision with another galaxy. When observed at longer wavelengths beyond visible light, the galaxy shows further disturbed patterns, including a filament of ionised hydrogen about 64,000 light-years long. IC 1459 is the anchor of a group of ten galaxies, and its complex kinematics make it an active subject of research into how elliptical galaxies assemble their mass over cosmic time.
10 NGC 7424: a mirror of the Milky Way next door
About 4 degrees west of the Grus Triplet lies NGC 7424, a barred spiral galaxy with an apparent magnitude of 10.4. At approximately 37.5 million light-years away, it is close enough that its structure is well defined, with clear spiral arms and an overall architecture thought to resemble the Milky Way — giving astronomers a rare outside view of something like our own home galaxy. Its diameter is approximately 100,000 light-years, comparable to standard estimates for the Milky Way itself. NGC 7424 has also been a site of violent stellar death: two ultraluminous X-ray sources and one supernova, designated SN 2001ig, have been observed within it. SN 2001ig was initially classified as a Type IIb supernova and showed a weak hydrogen line in its early spectrum. That signature later disappeared and was replaced by lines of oxygen, magnesium and calcium alongside features characteristic of a Type Ib supernova. A massive star of spectral type F, A, or B is thought to be the binary companion that survived the explosion of what was probably a Wolf-Rayet star.
11 Indigenous Australian sky: the Arrernte claim
One of the more unusual cultural stories attached to Grus comes from Central Australia. The Arrernte and Luritja peoples, living together at a mission in Hermannsburg, held a conception of the night sky that mapped onto their social geography: the sky was divided at the Milky Way, with stars to the east representing Arrernte camps and stars to the west representing Luritja camps. Alpha and Beta Gruis, along with Fomalhaut, Alpha Pavonis, and the stars of Musca, were all claimed as belonging to the Arrernte. This territorial reading of the sky reflects how deeply constellation-making is tied to local identity and social organisation — the same stars that Europeans named after a crane carried an entirely different meaning to people for whom the sky was literally a map of their community. The article does not record what specific meaning or story the Arrernte attached to the stars of Grus beyond this territorial association.
12 Gliese 832 and the nearest planetary systems Deeper
Among the six star systems in Grus confirmed to host planets, Gliese 832 stands out for its proximity. This red dwarf of spectral type M1.5V glows at apparent magnitude 8.66 and lies only 16.1 light-years from Earth, placing it among the nearest stars to the Solar System. In 2008, astronomers discovered that it hosts a Jupiter-like planet, designated Gliese 832 b, which completes an orbit every 9.4 ± 0.4 years — a period broadly similar to Jupiter's own 11.9-year orbit. The constellation also contains WASP-95, a sunlike star hosting a hot Jupiter, WASP-95b, that completes its orbit in just two days, representing the opposite extreme of planetary architecture: a massive world baking in the extreme heat of an orbit many times closer to its star than Mercury is to the Sun. Grus also contains WISE 2220−3628, a brown dwarf of spectral type Y — one of the coolest substellar objects known — calculated to lie about 26 light-years from Earth.