Wikipedia:Today's featured article/April 12, 2014

Triangulum Australe and Triangulum are two small constellations, both named for the triangular pattern of their three brightest stars. The constellations are in the far southern and the northern celestial hemispheres respectively. Triangulum Australe was first depicted as Triangulus Antarcticus by Petrus Plancius in 1589 and was given its current name by Johann Bayer in 1603. Its brightest star is Alpha Trianguli Australis, the 42nd-brightest star in the night sky. At magnitude 1.91, it is an orange giant that is 5500 times more luminous than, and 130 times as wide as, our Sun. One star system in Triangulum Australe has a confirmed planet. Triangulum was known to the ancient Babylonians and Greeks, and was one of the 48 constellations listed by the 2nd-century astronomer Ptolemy. It contains several galaxies, the brightest and nearest of which is the Triangulum Galaxy (pictured)—a member of the Local Group. It also contains 3C 48, the first quasar ever observed. At magnitude 3.00, the white giant star Beta Trianguli is the brightest star in Triangulum. Three stars in the constellation have been found to have planets. (Full articles: Triangulum Australe – Triangulum)

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