Grus

By BrightK self-checked Published 2026-09-04 Updated 2026-10-18 Editorial policy

• Constellations
• In the sky now

What is Grus?

Constellations· Autumn evenings low south (N) · the crane below Fomalhaut. Grus is a southern constellation shaped like a crane stretching its long neck, just south of the bright star Fomalhaut. From New York only its northern part rises above the southern horizon on autumn evenings, and from London almost none of it.

Stars of the figure

The 1 brightest of the 4 stars used in the figure (3 lines). Lower magnitude means brighter.

Constellation basics

Figures are representative approximations. Source: compiled from NASA and IAU public data.

The crane made from the Southern Fish's tail

The stars of Grus once belonged to another constellation. In Ptolemy's old star list they were recorded as stars in the tail of Piscis Austrinus, the Southern Fish. When the new constellation was drawn in 1598, the fish's tail became the crane's body. That is why the two constellations still sit right next to each other.

The name of its brightest star keeps a trace of this history. Alnair means "the bright one" in Arabic. It is the first part of a longer name meaning "the bright one of the fish's tail". Alnair is also one of the 57 navigational stars that ships have used to work out their position at sea.

In the south of Grus lie four galaxies called the Grus Quartet: NGC 7552, 7582, 7590 and 7599. About 60 million light-years away, they pull on one another with their gravity and are changing each other's shapes. From mid-northern latitudes this part of the sky stays very low or never rises (it is always below the horizon from London), so they are best observed from the southern hemisphere with a telescope.

The constellation in depth

Grus exists thanks to Dutch navigators of the late 16th century. On a voyage to the East Indies in 1595–97, Pieter Keyser and Frederick de Houtman measured the positions of southern stars. Using their records, Petrus Plancius put twelve new constellations on a globe in 1598, and Grus was one of them. For a time it was also known as the Flamingo.

Two bright stars sit side by side in the crane's body. Alpha, called Alnair, is a blue-white star of magnitude 1.7, and Beta is a red giant of about 2nd magnitude. Their colours are so different that the naked eye can see one is blue and one is red. A star's colour tells its surface temperature: Alnair's surface is hotter than 13,000 degrees, while red Beta is much cooler.

The crane's neck holds Delta and Mu Gruis. Each of them looks like two stars close together, even without a telescope. That gives the neck a knotted, jointed look. In each case, though, the two stars are not really near each other; they just happen to lie in the same direction as seen from Earth. Such chance pairs are called optical doubles.

On October–November evenings, look just above the southern horizon, right below the bright star Fomalhaut, for Alnair. From New York it climbs only about 2 degrees at best and from London it never rises, so you need a clear southern view. The whole figure is best seen from the southern hemisphere. From Sydney it rises almost overhead in the same season.

Frequently asked

When can I see Grus?

Grus is best seen in autumn evenings low south (N) · spring (S).

How do I find Grus?

To find Grus, look for directly south of Fomalhaut.

What is the brightest star in Grus?

The brightest star in Grus is Alnair, at magnitude 1.7.

Related

Figures are representative approximations. Simulated positions use J2000 mean elements.