Located in the southern sky, the constellation Grus is Latin for the crane, a type of bird. It is 1 of the 12 constellations conceived by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman. Grus first appeared on a 14 inch celestial globe published in 1598 in Amsterdam by Plancius and Jodocus Hondius. Johann Bayer depicted the constellation in his star atlas Uranometria of 1603.
French explorer and astronomer Nicolas-Louis de Lacaille gave Bayer designations to its stars in 1756. Some of these stars that received Bayer designations had been previously considered part of the neighboring constellation Piscis Austrinus. The constellations Grus, Pavo, Phoenix and Tucana are collectively known as the “Southern Birds”.
The constellation’s brightest star, Alpha Gruis, is also known as Alnair and appears as a 1.7-magnitude blue-white star. Beta Gruis is a red giant variable star with a minimum magnitude of 2.3 and a maximum magnitude of 2.0. Six star systems have been found to have planets. Deep-sky objects found in Grus include the planetary nebula IC 5148, also known as the Spare Tyre Nebula, and a group of four interacting galaxies known as the Grus Quartet.
Applicable Information | |
Visibility In Pacific Northwest | Partially Available–Only 1st Half. July to November |
Best Times To View | October |
Right Ascension | 21h 27.4m to 23h 27.1m |
Declination | −36.31° to −56.39° |
Area | 366 square degrees |
Main Stars | 8 |
Brightest Object | α Gru (Alnair) |
Meteor showers | 0 |
Messier objects | 0 |
Neighboring Constellations | Piscis Austrinus, Microscopium, Indus, Tucana, Phoenix, Sculptor |
History
The stars that form Grus were originally considered part of the neighboring constellation Piscis Austrinus, with Gamma Gruis seen as part of the fish’s tail. The stars were first defined as a separate constellation by the Dutch astronomer Petrus Plancius, who created 12 new constellations based on the observations of the southern sky by the Dutch explorers. These observations by Dutch explorers were taken during the first Dutch expedition to the East Indies.
Grus first appeared on a celestial globe published in 1598 in Amsterdam by Plancius. Its first depiction in a celestial atlas was in the German cartographer Johann Bayer’s Uranometria of 1603.
The stars that correspond to Grus were generally too far south to be seen from China. In Central Australia, the Arrernte and Luritja people living on a mission in Hermannsburg viewed the sky as divided between them, east of the Milky Way representing Arrernte camps and west denoting Luritja camps. Alpha and Beta Gruis, along with Fomalhaut, Alpha Pavonis and the stars of Musca, were all claimed by the Arrernte.
Stars
There are 12 stars that were assigned by Keyser and de Houtman to Grus. . Bayer depicted Grus on his chart, but did not assign its stars Bayer designations. In 1756, French explorer and astronomer Nicolas-Louis de Lacaille labelled the stars from Alpha to Phi with some omissions. In 1879, American astronomer Benjamin Gould added Kappa, Nu, Omicron and Xi, which had all been catalogued by Lacaille but not given Bayer designations. Lacaille considered them too faint, while Gould thought otherwise.
Some of the interesting dark sky objects in the Grus constellation are four interacting galaxies known as the Grus Quartet, which are NGC 7552, NGC 7590, NGC 7599, and NGC 7582. The latter three galaxies occupy an area of sky only 10 arcminutes across and are sometimes referred to as the “Grus Triplet.” NGC 7552 and 7582 are exhibiting high starburst activity.
NGC 7424 is a barred spiral galaxy with an apparent magnitude of 10.4. located around 4 degrees west of the Grus Triplet. The galaxy is notable as it has well defined spiral arms and is thought to resemble the Milky Way.
Located near Alnair is NGC 7213, which is a type 1 Seyfert galaxy located approximately 71.7 million light-years from Earth. It has an apparent magnitude of 12.1 and appears undisturbed in visible light, which scientists think shows as signs of having undergone a collision or merger.
NGC 7410 is a spiral galaxy with a visual magnitude oof 11.7 and is 122 million light years from Earth. It was discovered in 1834 by British astronomer John Herschel during observations at the Cape of Good Hope.
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