Crux Constellation: The Ultimate Guide

The Australian Aborigines recognized the Southern Cross and attributed different names and origins.

In Australian Aboriginal astronomy, the Coal Sack Nebula and the Southern Cross mark the head of the "emu in the sky" in various Aboriginal cultures. The cross is also considered the representation of a Postum sitting on a tree and a symbol of the heavenly deity Mirrabooka.

Maori, who call it Te Punga ('the anchor'), represents the anchor of the waka, or canoe, of Tama-rereti, symbolized by the Milky Way. In addition, the constellation was used in its travels through the Pacific to locate the south and not get lost in the sea.

The ancient Greeks did not recognize the constellation Crux as an independent constellation since it was not visible all year round and was hidden during the spring and summer.

The constellation Crux appears on celestial maps but as part of the constellation Centaurus.

During the fifth century, when the era of exploration began for more, the constellation Crux began to take importance for the northern hemisphere inhabitants, but mainly for sailors and pirates.

Ship captains used the constellation Crux to locate the southern hemisphere to avoid getting lost at sea.

Then during the nineteenth century, the International Astronomical Union realized that the constellation Crux was too crucial for the cultures of the southern hemisphere, so it was decided to separate it from the constellation Centaurus and consider it as an independent constellation.

Currently, the constellation Crux remains within the boundaries imposed by the International Astronomical Union and has not undergone modifications since then.

It is also considered one of the most actual constellations due to its brightness and shape, which makes it very easy to find in the sky.

Crux resides in the third quadrant of the Southern Hemisphere (SQ3) at latitudes between 20° N and 90° S, which means that we can see the constellation in the night sky from all countries of the southern hemisphere of the earth and some countries of the northern hemisphere.

Crux's constellation is visible in South America, Asia, Australia, and Antarctica.

The crux is not visible in areas above 20° N latitude, such as the USA, Europe, Russia, China, Japan, northern Mexico, or Egypt.

The Crux is a circumpolar constellation most visible during the spring; however, May is the best month to visualize it.

In the northern hemisphere, the constellation Crux is not visible during the summer, autumn, and winter; the only date on which it can be observed is during the spring.

The Crux is essentially located near the south pole, so if you're in the northern hemisphere, you'll have to turn your gaze south.

The easiest way to find it is by looking south and locating the bright stars Acrux and Mimosa, which form the central figure of the Southern Cross and lie just below the constellation Centaurus.

The constellations bordering Crux are Centaurus and Musca. In addition, the constellation Crux also belongs to the Hercules family of constellations; these include Aquila, Ara, Centaurus, Corona Australis, Corvus, Crater, Cygnus, Hercules, Hydra, Lupus, Lyra, Ophiuchus, Sagitta, Scutum, Sextans, Serpens, and Triangulum.

The constellation Crux officially contains 49 stars, of which 5 form the central figure of the constellation; these are Acrux, Mimosa, Gacrux, and Decrux.

It is the brightest star in the constellation Crux with an apparent magnitude of +1.30 and lies at 280 light-years from Earth.

It is a subgiant star of visual magnitude +1.30 of blue color and spectral type B0.5IV

With an apparent magnitude of +0.77, Ácrux is 325 light-years from the solar system, the second brightest star in the constellation Crux.

Ácrux is composed of two bluish-white stars; Alpha-1 Crucis (HD 108248 / HR 4730) is a subgiant of spectral type B0.5IV and magnitude 1.33.

Alpha-2 Crucis (HD 108249 /HR 4731) is a B1V-type star of magnitude 1.7 of the main sequence.

With an apparent magnitude of +1.63, Gacrux is the third brightest star in the constellation Crux, lies 88 light-years from the earth.

Gacrux is a red giant of spectral type M3.5III with a surface temperature of 3400 K.

It is a bluish-white star of spectral type B2IV with a temperature of 22,550 K.

Imai is the fourth brightest star in the constellation of the Southern Cross with an apparent magnitude of +2.77 and is located 360 light-years from Earth.

The Crux is also known as the home of several deep-sky objects. Deep-sky objects often mean star clusters, nebulae (interstellar cloud bodies), or galaxies.

In the case of Crux, it is rich in nebulae and star clusters, being one of the constellations with the most incredible diversity of deep-sky bodies.

This cumulus takes its name from the diversity of colors presented by its stars and resembles the brightness of the "jewels."

NGC 4755 is in the constellation of Crux has Bayer designation; However, it is a group rather than an individual star. The current designation Kappa Crucis is used for the HD star 111973.

• The Coal Sack Nebula: It is one of the darkest and densest. It was observed by the Spanish navigator and conquistador Vicente Yáñez Pinzón in 1499.
• The Dragon Fish Nebula: Contains what may be the most significant and brightest stellar association in our galaxy.
• NGC 4609 (also Collinder 263 or Caldwell 98): It is an open star cluster that can be seen very close to the variable star BZ Crucis immersed in the Carbon Sac Nebula.

• Because it is a symbol that represents the south, currently, many countries in the southern hemisphere have in their flags the constellation Crux; some of these are the flags of Australia, New Zealand, Papua New Guinea, Brazil, among many others.
• The cultures of the southern hemisphere always considered the Crux constellation as an independent constellation. In contrast, the cultures of the northern hemisphere always related it to the constellation Centaurus because, in the north, the constellation Crux is not always visible.
• The constellation Crux was not relieved until the era of sea exploration began when sailors began to use this constellation to locate the south.

• The Crux is a constellation located primarily in the southern hemisphere; its name is derived from its shape since it has the shape of a cross, although, in different cultures, it has been given other names associated with deities of creation.
• The Crux is a more popular constellation in the southern hemisphere than in the northern hemisphere as it is present in different cultures of antiquity, such as the Aborigines of Australia.
• The Crux constellation is the minor constellation in the sky, despite that it is one of the most important due to its shape and stars of intense brightness.
• The best month to see the Crux constellation is in May, between the latitudes of 20° N and 90° S.
• The easiest way to locate the constellation Crux is by drawing an imaginary straight line from the star Epsilon Centauri to Lambda Centauri; both stars belong to the constellation Centaurus. Crux's constellation is located right in the middle of the road between those two stars.
• The brightest star in Cetus is Beta Crucis (Mimosa / β Cru), with an apparent magnitude of +1.30.
• Crux's most notable deep sky body is the open stellar cumulus NGC 4755 or Kappa Crucis.

1. https://www.universeguide.com/constellation/crux
2. https://www.constellation-guide.com/constellation-list/crux-constellation/
3. https://star-name-registry.com/constellations/crux
4. https://www.abc.net.au/news/science/2016-05-02/may-sky-guide/7356040
5. http://www.seasky.org/constellations/constellation-crux.html