Grus is a constellation in the southern sky. Its name is Latin for the Crane, a type of bird. It is one of twelve constellations conceived by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman. Grus first appeared on a 35-cm (14 in) diameter celestial globe published in 1598 in Amsterdam by Plancius and Jodocus Hondius and was depicted in Johann Bayer's star atlas Uranometria of 1603.
The constellation, a southern group and lies beneath the
bright star Fomalhaut in the constellation of Piscis Austrinus. Grus cannot be
seen from Britain.
The Arab astronomer Al Sufi who produced a star map in 964CE placed most of the stars in Grus into the constellation of Piscis Austrinus.
Alpha or Al Nair which means the ‘Bright One of the tail of
the fish ’ this is because it was originally in the tail of Piscis Austrinus.
It shines at a magnitude of 1.7 and is 101 light years away, Al Nair is a B
class star much hotter than the Sun.
Beta is a red giant of class M5 making it much cooler than
the Sun and is around 170 light-years from Earth. Beta varies in brightness
between magnitude 2.0- 2.3.
Lying in the north-west corner of Grus is the star gamma
whose name is Al Dhanab which means the tail of the fish. Today it marks the
eye of the crane. Al Dhanab shines at a magnitude 3.0 and is a B class giant
star with surface temperature 12,500 and lies 211 light years from Earth.
There are no bright deep sky objects in Grus.
www.theramblingastronomer.co.uk
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