The constellations of Apus (the Bird of Paradise), Triangulum Australe (the Southern Triangle) and Circinus (the Compasses). The three constellations lie in the southern hemisphere, near the celestial pole, and cannot be seen from northern latitudes. They were named when European explorers first headed southward across the equator, although the three brightest stars of Triangulum Australe were used by ancient seafarers for navigation. Both Apus and Triangulum Australe were described in 1603 in the first all-sky star atlas, Johan Bayer's Uranometria. Nicolas Lacaille added Circinus in 1752. The two brightest stars in the image (upper right) are Alpha and Beta Centauri. See Observing the Constellations", pages 16 & 66."