Triangulum Australe is a very small constellation in the southern hemisphere. It was introduced by the Dutch astronomer Petrus Plancius from the observations of 16th century Dutch navigators, and it first appeared in a celestial atlas in German uranographer Johann Bayer's Uranometria in 1603. In Latin, Triangulum Australe means "the southern triangle." The three brightest stars in the constellation form a nearly equilateral triangle.
The constellation Triangulum Australe occupies an area of 110 square degrees and contains one star with known planets. It can be seen at latitudes between +25° and -90° and is best visible at 9 p.m. during the month of July.
The brightest star in the constellation is 
alpha Trianguli Australis, also known as Atria, which is just a contraction of its designation. It is an orange bright giant 415 light-years distant and a suspected binary star.
beta Trianguli Australis is a binary star consisting of a yellow-white giant and a faint, magnitude 14 companion star. The system is about 40.1 light-years distant.
gamma Trianguli Australis is a white dwarf approximately 183 light-years distant.
delta Trianguli Australis is another binary star, 621 light-years away from Earth. It consists of a yellow supergiant and a magnitude 12 companion. The primary component has an apparent magnitude of 3.86.
iota Trianguli Australis is a triple star lying about 132 light-years away. The primary component consists of two yellow-white stars and the third component is a faint, magnitude 10 star.
theta Trianguli Australis is a yellow giant that lies about 328 light-years from Earth.
Triangulum Australe also contains a notable deep sky object. NGC 6025 is an open star cluster consisting of about 30 stars between 7th and 9th magnitude. The cluster lies approximately 2,700 light-years away. It was first discovered by the French astronomer Nicolas Louis de Lacaille in the 18th century.
Triangulum Australe belongs to the Hercules family of constellations, along with Hercules
, Corona Australis
Constellations directly bordering Triangulum Australe are Norma