Definition of Crux (Southern Cross)

Constellations are a set of stars grouped together by some kind of imaginary line. They form silhouettes and images singular. Some of them can be recognized with the naked eye and without the need to use any telescope, such as Ursa Major, Ursa Minor, Orion or the Southern Cross.

The Southern Cross, also known as Crux or Crux Australis, is so named because its location is close to the South Pole and because it is opposed to another constellation similar, the Northern Cross. It is a circumpolar constellation, which means that an observer of a latitude he can always watch her.

Of the 88 constellations of the Milky Way, is the smallest of all and has traditionally been very useful in navigation to identify the position of the Earth's South Pole and the cardinal points. The four stars that form it are Acrux, Becrux, Gacrux and Decrux. When looking at the Crux with the naked eye, it appears as a bright spot embedded in the Milky Way.

Despite its small size, the Crux is taken as an astronomical reference to locate other constellations and space phenomena, such as the star cluster known as NGC 4755 or the Jeweler.

Its symbolic and historical dimension

The flag of Australia, Brazil, New Guinea, Samoa and New Zealand includes the picture of this constellation, since these nations are in the southern hemisphere of the planet. The Province Argentina from Tierra del Fuego also includes this image on its flag. If viewed from the city of Buenos Aires, the Crux remains visible throughout the year.

In the cultures of South America, the Crux was associated with a sacred animal, the ñandú (this animal was sacred in the Mapuche, Araucanian and Guaraní cultures)

Many Inca constructions include the four stars of this constellation. The ancient inhabitants of the Caribbean observed the sky as a reference for the cycles of the farming and when they distinguished the Crux they knew that it was the ideal time for planting the corn.

In the astronomical descriptions of Ptolemy in the Almagest reference is made to the grouping of these stars (in the 2nd century AD. C astronomers placed it within the constellation Centaurus). However, it was in 1505 when the Portuguese sailor Hernando de Magallanes used the term Cruz del Sur (Cruz do Sul). Previously, characters such as Marco Polo or Américo Vespucio had mentioned it with other names.

Photo Fotolia: Layritten