The Southern Cross

DavidReneke has an article on the Southern Cross, a constellation beloved of those living in the Southern hemisphere.

And he explains that the brightest star at the bottom of the constellation is actually a more than one star:

Acrux is about 321 light-years from Earth, and in fact it is not one star but two nearly identical B-class stars. These can be resolved in a small telescope, making Acrux a nice double, but they appear as a single star to the unaided human eye. The brighter of the two — call it Alpha-1, is magnitude 1.33 and the dimmer — call it Alpha-2 –1.73, with a resultant magnitude of 0.77. ,,,

  To make things even more complicated, it appears that Alpha-1 is in fact a double star, whose components’ combined masses are about 24 times that of the sun. Alpha-2 is a single star about 13 times as massive as the sun. Acrux’s position is RA: 12h 26m 35s, dec: -63° 05′ 57″. Source: Earth and Sky

he says that MarkTwain wasn't impressed when he saw it, but when I worked in Africa, at night I could see it in the south, hanging in the sky over the distant slag heap from an asbestos mine 20 milessouth of us. This is the closet photo to what I remember seeing:

Can we see it from here? no. Presumably we are too far north to see it.

but in the past, those in the northern hemisphere could indeed view the constellation:

 here is another factoid about the constellation. from GlobeAtNight:

Crux was visible to the Ancient Greeks, who regarded it as part of the constellation Centaurus. At the latitude of Athens in 1000 BC, Crux was clearly visible, though low in the sky. However, the precession of the equinoxes gradually lowered Crux’s stars below the European horizon, and they were eventually forgotten by the inhabitants of northern latitudes. By AD 400, most of the constellation never rose above the horizon for Athenians.