of the southern stars. Also depicting it as a surveyor's level, German Johann Bode gave it the alternate name of Libella in his Uranographia. German poet and author Philippus Caesius saw the three main stars as representing the Three Patriarchs, Abraham, Isaac and Jacob (with Atria as Abraham). The Wardaman people of the Northern Territory in Australia perceived the stars of Triangulum Australe as the tail of the Rainbow Serpent, which stretched out from near Crux across to Scorpius. Overhead in October, the Rainbow Serpent "gives Lightning a nudge" to bring on the wet season rains in November. Characteristics Triangulum Australe is a small constellation bordered by Norma to the north, Circinus to the west, Apus to the south and Ara to the east. It lies near the Pointers (Alpha and Beta Centauri), with only Circinus in between. The constellation is located within the Milky Way, and hence has many stars. A roughly equilateral triangle, it is easily identifiable. Triangulum Australe lies too far south in the celestial southern hemisphere to be visible from Europe, yet is circumpolar from most of the southern hemisphere. The three-letter abbreviation for the constellation, as adopted by the International Astronomical Union in 1922, is "TrA". The official constellation boundaries, as set by Belgian astronomer Eugène Delporte in 1930, are defined by a polygon of 18 segments. In the equatorial coordinate system, the right ascension coordinates of these borders lie between and , while the declination coordinates are between −60.26° and −70.51°. Triangulum Australe culminates each year at 9 p.m. on 23 August. Notable features Bright stars In defining the constellation, Lacaille gave twelve stars Bayer designations of Alpha through to Lambda, with two close stars called Eta (one now known by its Henry Draper catalogue number), while Lambda was later dropped due to its dimness. The three brightest stars, Alpha, Beta and Gamma, make up the triangle. Readily identified by its orange hue, Alpha Trianguli Australis is a bright giant star of spectral type K2 IIb-IIIa with an apparent magnitude of +1.91 that is the 42nd-brightest star in the night sky. It lies away and has an absolute magnitude of −3.68 and is 5,500 times more luminous than the Sun. With a diameter 130 times that of the Sun, it would almost reach the orbit of Venus if placed at the centre of the Solar System. The proper name Atria is a contraction of