Crux few bright stars of importance lie between Crux and the pole itself, although the constellation Musca is fairly easily recognised immediately beneath Crux. A technique used in the field is to clench one's right fist and to view the cross, aligning the first knuckle with the axis of the cross. The tip of the thumb will indicate south. Argentine gauchos are well known for using it for night orientation in the vast Pampas and Patagonic regions. Within the constellation's borders, there are 49 stars brighter than or equal to apparent magnitude 6.5. The four main stars that form the asterism
Crux the Coalsack Nebula. The stars within Crux were known to the Ancient Greeks, where Ptolemy regarded them as part of the constellation Centaurus. They were entirely visible as far north as Britain in the fourth millennium BC. However, the precession of the equinoxes gradually lowered the stars below the European horizon, and they were eventually forgotten by the inhabitants of northern latitudes. By 400 AD, most of the stars in the constellation we now call Crux never rose above the horizon of Athens. The 15th century Venetian navigator Alvise Cadamosto made note of what was probably the Southern Cross on