# Grus (constellation)

**Grus** (abbreviation Gru, genitive Gruis) is a southern constellation representing the crane, one of the 88 constellations officially recognized by the International Astronomical Union.<sup>[1](https://www.iau.org/IAU/IAU/Astronomy-FAQs/Constellations.aspx?hkey=bb9dc841-0618-41b5-ac70-149741062141)</sup> It lies south of [Piscis Austrinus](https://www.edgepedia.org/piscis-austrinus) and the bright star Fomalhaut, covers 366 square degrees, and is best seen from the [Southern Hemisphere](https://www.edgepedia.org/southern-hemisphere), where its bright stars form a recognizable pattern.<sup>[2](https://www.constellationdirectory.org/constellations/grus.html)</sup><sup> • </sup><sup>[3](https://www.phys.ttu.edu/~ozprof/grus.htm)</sup>

| Key fact | Detail |
|---|---|
| Official designation | Grus, "The Crane"; abbreviation Gru; genitive Gruis; one of the 88 IAU constellations<sup>[1](https://www.iau.org/IAU/IAU/Astronomy-FAQs/Constellations.aspx?hkey=bb9dc841-0618-41b5-ac70-149741062141)</sup> |
| Position and size | Right ascension 22.61 h, declination −44.52°, area 366 square degrees<sup>[2](https://www.constellationdirectory.org/constellations/grus.html)</sup> |
| Origin | One of twelve southern constellations recorded on the Dutch East Indies voyage of 1595–1597; named in Johann Bayer's Uranometria (1603)<sup>[4](https://astronomy.hk/en/constellations/gru)</sup><sup> • </sup><sup>[2](https://www.constellationdirectory.org/constellations/grus.html)</sup>  |
| Brightest star | Alnair (Alpha Gruis), magnitude 1.73, spectral type B6 V, about 101 light-years away<sup>[5](https://simbad.u-strasbg.fr/simbad/sim-basic?Ident=Alpha+Gruis)</sup> |
| Notable star | π¹ Gruis, a red giant 530 light-years away with 350 times the Sun's diameter, imaged in detail by ESO's Very Large Telescope in 2017<sup>[6](https://www.eso.org/public/news/eso1741/)</sup> |
| Deep-sky objects | The planetary nebula IC 5148 ("Spare Tyre Nebula"), the spiral galaxy NGC 7424, and the Grus Quartet of galaxies<sup>[7](https://www.eso.org/public/images/potw1242a/)</sup><sup> • </sup><sup>[8](https://science.nasa.gov/asset/hubble/compass-image-for-ngc-7424/)</sup><sup> • </sup><sup>[9](https://nowsky.org/i/con-grus)</sup>  |
| Best viewing | October evenings; naked-eye visibility from latitudes south of +33°<sup>[2](https://www.constellationdirectory.org/constellations/grus.html)</sup> |

## Location and visibility

Grus sits in the southern sky roughly halfway between the celestial equator and the south celestial pole.<sup>[10](https://www2.arnes.si/~ucotar/astro/Sky%26Telescope/2025/aas_st_202510.pdf)</sup> Its declination range of about −36° to −55° keeps it little known to northern observers, but from the Southern Hemisphere it is a well-known and easily recognized constellation.<sup>[3](https://www.phys.ttu.edu/~ozprof/grus.htm)</sup> The whole constellation is visible at some point in the year from everywhere in the Southern Hemisphere, and also from equatorial and some temperate northern regions; it is best viewed in the evening during the northern autumn and southern spring.<sup>[11](https://astro4edu.org/resources/diagram/ad16OT55f845/)</sup> One observing guide places naked-eye visibility from latitudes south of 33° North during July through September.<sup>[12](https://www.astronomical.org/constellationsCopy/gru.html)</sup>

The constellation is surrounded by Piscis Austrinus, Microscopium, Indus, Tucana, Phoenix, and Sculptor.<sup>[11](https://astro4edu.org/resources/diagram/ad16OT55f845/)</sup> Its pattern is anchored by Alnair, a first-magnitude-class blue-white star, with the red giant Beta Gruis forming part of the bird's body; the two make a conspicuous color-contrast pair visible to the naked eye.<sup>[13](https://opdtechnologies.com/celestial/grus/)</sup><sup> • </sup><sup>[3](https://www.phys.ttu.edu/~ozprof/grus.htm)</sup>

## History

Grus is one of the twelve southern constellations recorded during the [Dutch East Indies](https://www.edgepedia.org/dutch-east-indies) voyage of 1595 to 1597, based on observations made by the navigators Pieter Dirkszoon Keyser and Frederick de Houtman.<sup>[4](https://astronomy.hk/en/constellations/gru)</sup><sup> • </sup><sup>[14](https://newnetherlandinstitute.org/content/pieter-dirkszoon-keyser-and-the-mapping-of-the-southern-sky/)</sup>  The twelve, which also include Phoenix, Tucana, Pavo, Hydrus, and Indus, first appeared on a celestial globe completed by 1598 by the cartographer Petrus Plancius with Jodocus Hondius, and were named in their modern form by Johann Bayer in his 1603 star atlas *Uranometria*.<sup>[2](https://www.constellationdirectory.org/constellations/grus.html)</sup><sup> • </sup><sup>[15](https://exhibitions.lib.udel.edu/multiple-middles/wp-content/uploads/sites/239/2022/03/mm-catalog-final-compressed.pdf)</sup>  Grus, Phoenix, Tucana, and Pavo together make up the "southern birds," adjoining constellations designed as a group from the same Dutch observations.<sup>[4](https://astronomy.hk/en/constellations/gru)</sup>

Before its current name, the constellation was designated [Phoenicopterus](https://www.edgepedia.org/phoenicopterus), the Flamingo.<sup>[2](https://www.constellationdirectory.org/constellations/grus.html)</sup> Its stars had earlier been grouped with Piscis Austrinus, the Southern Fish; the Arabic name of Alnair, "the bright one," originally referred to the fish's tail, since the fish constellation then extended over the stars of Grus.<sup>[2](https://www.constellationdirectory.org/constellations/grus.html)</sup><sup> • </sup><sup>[16](https://astrologyking.com/grus-constellation/)</sup>  Unlike the ancient constellations, Grus has no mythology attached to it.<sup>[2](https://www.constellationdirectory.org/constellations/grus.html)</sup>

## Bright stars

**Alnair.** [Alpha Gruis](https://www.edgepedia.org/alpha-gruis), called Alnair, is the brightest star of Grus at magnitude 1.73, a blue-white star of spectral type B6 V about 101 light-years from Earth.<sup>[5](https://simbad.u-strasbg.fr/simbad/sim-basic?Ident=Alpha+Gruis)</sup> Its name means "the bright one" in Arabic.<sup>[17](https://earthsky.org/constellations/grus-the-crane-the-bright-one/)</sup>

**Beta Gruis.** The second-brightest star is a red giant of about magnitude 2.1 whose orange-red hue is visible to the naked eye and contrasts with Alnair's blue-white light.<sup>[9](https://nowsky.org/i/con-grus)</sup><sup> • </sup><sup>[13](https://opdtechnologies.com/celestial/grus/)</sup>

**π¹ Gruis.** This red giant lies 530 light-years away and has about the same mass as the Sun but 350 times its diameter.<sup>[6](https://www.eso.org/public/news/eso1741/)</sup> In 2017 an international team led by Claudia Paladini of the [European Southern Observatory](https://www.edgepedia.org/european-southern-observatory) used the PIONIER instrument on the [Very Large Telescope](https://www.edgepedia.org/very-large-telescope) to image its surface, revealing a small number of convective cells, or granules, each about 120 million kilometers across, roughly a quarter of the star's diameter; one such cell would span the distance from the Sun to beyond Venus.<sup>[6](https://www.eso.org/public/news/eso1741/)</sup> By comparison, the Sun's photosphere holds about two million convective cells of roughly 1,500 kilometers each.<sup>[6](https://www.eso.org/public/news/eso1741/)</sup> π¹ Gruis is also the brighter member of a contrasting-color pair with π² Gruis, and Thomas Brisbane recognized in the 1830s that π¹ Gruis itself is a close binary system.<sup>[6](https://www.eso.org/public/news/eso1741/)</sup>

## Deep-sky objects

**IC 5148.** This planetary nebula, nicknamed the Spare Tyre Nebula for its ring-like appearance in small telescopes, lies about 3,000 light-years away in Grus, about 1 degree west of Lambda Gruis.<sup>[7](https://www.eso.org/public/images/potw1242a/)</sup><sup> • </sup><sup>[18](https://www.rasc.ca/sites/default/files/World%20Asterisms%20Project%20Handbook%20V%202025.14.pdf)</sup>  It is a couple of light-years across and still expanding at over 50 kilometers per second, one of the fastest-expanding planetary nebulae known.<sup>[7](https://www.eso.org/public/images/potw1242a/)</sup> [The Australian](https://www.edgepedia.org/the-australian) amateur astronomer Walter Frederick Gale discovered it in 1894.<sup>[18](https://www.rasc.ca/sites/default/files/World%20Asterisms%20Project%20Handbook%20V%202025.14.pdf)</sup> A detailed study based on ESO La Silla observations derived an expansion velocity of 47.9 ± 1.5 km/s and a model age of 8,500 years, and traced an ionized halo extending to a radius of about 100 arcseconds.<sup>[19](https://arxiv.org/abs/1810.01350)</sup>

**NGC 7424.** This barred spiral galaxy lies in Grus and was home to supernova SN 2001ig, which exploded about 40 million light-years away and was photographed by the European Southern Observatory's Very Large Telescope in 2002; Hubble observations in 2016 pinpointed a surviving binary companion, evidence that some supernovae originate in double-star systems.<sup>[8](https://science.nasa.gov/asset/hubble/compass-image-for-ngc-7424/)</sup> NASA's object page gives the galaxy's distance as 37.5 million light-years, while an Astronomy Picture of the Day description places it about 40 million light-years away and notes its size of roughly 100,000 light-years, similar to the [Milky Way](https://www.edgepedia.org/milky-way).<sup>[8](https://science.nasa.gov/asset/hubble/compass-image-for-ngc-7424/)</sup><sup> • </sup><sup>[20](https://apod.nasa.gov/apod/ap130108.html)</sup>

**Galaxy groups.** The constellation contains the Grus Quartet, a group of four galaxies cataloged as NGC 7552, 7582, 7590, and 7599.<sup>[9](https://nowsky.org/i/con-grus)</sup> Near Alnair itself sits NGC 7213, a magnitude 10.5 active galaxy about 16 arcminutes from the star, which observations with [XMM-Newton](https://www.edgepedia.org/xmm-newton) showed to have intermediate X-ray properties between weak active nuclei and higher-luminosity Seyfert galaxies.<sup>[17](https://earthsky.org/constellations/grus-the-crane-the-bright-one/)</sup><sup> • </sup><sup>[21](https://arxiv.org/abs/astro-ph/0412017)</sup>  Other cataloged galaxies in the constellation include NGC 7130, NGC 7418, NGC 7421, IC 1459, and IC 5264.<sup>[2](https://www.constellationdirectory.org/constellations/grus.html)</sup>

## Observing notes

For observers with modest equipment, Grus offers mainly its naked-eye stars; one guide states that the constellation holds no good deep-sky targets for small instruments, with the brightest-star field around Alnair and the nearby NGC 7213 as the main telescopic option.<sup>[17](https://earthsky.org/constellations/grus-the-crane-the-bright-one/)</sup> The line of naked-eye double stars marking the crane's neck ends at Gamma Gruis, with IC 5148 two degrees to the west.<sup>[3](https://www.phys.ttu.edu/~ozprof/grus.htm)</sup> The constellation's southerly position gives Southern Hemisphere observers a favorable window on the galaxies and nebulae of this region of sky.<sup>[22](https://www.go-astronomy.com/constellations.php?Name=Grus)</sup>

## References

1. [The Constellations, IAU](https://www.iau.org/IAU/IAU/Astronomy-FAQs/Constellations.aspx?hkey=bb9dc841-0618-41b5-ac70-149741062141)
2. [Grus, The Constellation Directory](https://www.constellationdirectory.org/constellations/grus.html)
3. [Grus, Texas Tech University Physics Department](https://www.phys.ttu.edu/~ozprof/grus.htm)
4. [Grus, Astronomy.HK](https://astronomy.hk/en/constellations/gru)
5. [Alpha Gruis, SIMBAD Astronomical Database, CDS Strasbourg](https://simbad.u-strasbg.fr/simbad/sim-basic?Ident=Alpha+Gruis)
6. [Giant Bubbles on Red Giant Star's Surface, ESO](https://www.eso.org/public/news/eso1741/)
7. [From Cosmic Spare Tyre to Ethereal Blossom, ESO](https://www.eso.org/public/images/potw1242a/)
8. [Compass Image for NGC 7424, NASA Science](https://science.nasa.gov/asset/hubble/compass-image-for-ngc-7424/)
9. [Grus, NowSky](https://nowsky.org/i/con-grus)
10. [October 2025 Observing, Sky & Telescope](https://www2.arnes.si/~ucotar/astro/Sky%26Telescope/2025/aas_st_202510.pdf)
11. [Grus Constellation Map, IAU Office of Astronomy for Education](https://astro4edu.org/resources/diagram/ad16OT55f845/)
12. [PAS Constellations: Gru, Peoria Astronomical Society](https://www.astronomical.org/constellationsCopy/gru.html)
13. [Grus, OPD Technologies Celestial Archive](https://opdtechnologies.com/celestial/grus/)
14. [Pieter Dirkszoon Keyser and the Mapping of the Southern Sky, New Netherland Institute](https://newnetherlandinstitute.org/content/pieter-dirkszoon-keyser-and-the-mapping-of-the-southern-sky/)
15. [Celestial cartography catalog, University of Delaware exhibitions](https://exhibitions.lib.udel.edu/multiple-middles/wp-content/uploads/sites/239/2022/03/mm-catalog-final-compressed.pdf)
16. [Grus Constellation, Astrology King](https://astrologyking.com/grus-constellation/)
17. [Grus the Crane, home to 'the bright one', EarthSky](https://earthsky.org/constellations/grus-the-crane-the-bright-one/)
18. [World Asterisms Project Handbook, Royal Astronomical Society of Canada](https://www.rasc.ca/sites/default/files/World%20Asterisms%20Project%20Handbook%20V%202025.14.pdf)
19. [The planetary nebula IC 5148 and its ionized halo, arXiv](https://arxiv.org/abs/1810.01350)
20. [Grand Spiral Galaxy NGC 7424, Astronomy Picture of the Day, NASA](https://apod.nasa.gov/apod/ap130108.html)
21. [The Seyfert-LINER Galaxy NGC 7213: An XMM-Newton Observation, arXiv](https://arxiv.org/abs/astro-ph/0412017)
22. [Grus Constellation, Go Astronomy](https://www.go-astronomy.com/constellations.php?Name=Grus)

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*Topic: Encyclopedia › Physical world and mathematics › Astronomy › Stars and galaxies › Constellations, star names, and catalogs › Individual constellations*

*Initially written Sep 17, 2026 · Reviewed: Oct 15, 2026 · Edited: Oct 15, 2026 · Last review: Oct 15, 2026*

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License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license