star as Eta as well, which was inconsistently followed by Francis Baily, who used the name for the brighter or both stars in two different publications. Despite their faintness, Benjamin Gould upheld their Bayer designation as they were closer than 25 degrees to the south celestial pole. The second Eta is now designated as HD 150550. It is a variable star of average magnitude 6.53 and spectral type A1III. Variable stars Triangulum Australe contains several cepheid variables, all of which are too faint to be seen with the naked eye: R Trianguli Australis ranges from apparent magnitude 6.4 to 6.9 over a period of 3.389 days, S Trianguli Australis varies from magnitude 6.1 to 6.8 over 6.323 days, and U Trianguli Australis' brightness changes from 7.5 to 8.3 over 2.568 days. All three are yellow-white giants of spectral type F7Ib/II, F8II, and F8Ib/II respectively. RT Trianguli Australis is an unusual cepheid variable which shows strong absorption bands in molecular fragments of C2, ⫶CH and ⋅CN, and has been classified as a carbon cepheid of spectral type R. It varies between magnitudes 9.2 and 9.97 over 1.95 days. Lying nearby Gamma, X Trianguli Australis is a variable carbon star with an average magnitude of 5.63. It has two periods of around 385 and 455 days, and is of spectral type C5, 5(Nb). EK Trianguli Australis, a dwarf nova of the SU Ursae Majoris type, was first noticed in 1978 and officially described in 1980. It consists of a white dwarf and a donor star which orbit each other every 1.5 hours. The white dwarf sucks matter from the other star onto an accretion disc and periodically erupts, reaching magnitude 11.2 in superoutbursts, 12.1 in normal outbursts and remaining at magnitude 16.7 when quiet. NR Trianguli Australis was a slow nova which peaked at magnitude 8.4 in April 2008, before fading to magnitude 12.4 by September of that year. Deep-sky objects Triangulum Australe has few deep-sky objects—one open cluster and a few planetary nebulae and faint galaxies. NGC 6025 is an open cluster with about 30 stars ranging from 7th to 9th magnitude. Located 3 degrees north and 1 east of Beta Trianguli Australis, it lies about away and is about in diameter. Its brightest star is MQ Trianguli Australis at apparent magnitude 7.1. NGC 5979, a planetary nebula of apparent magnitude 12.3, has a blue-green hue at higher magnifications, while Henize