COSMOS / CONSTELLATIONS / TRA
Triangulum Australe (Southern Triangle)
The Southern Triangle. IAU abbreviation TrA. One of the 12 southern constellations based on the observations of the Dutch navigators Pieter Dirkszoon Keyser and Frederick de Houtman on their 1595–1597 voyage and spread by the globes of Petrus Plancius.
STAR CHART
KEY FACTS
- IAU abbreviation
- TrA
- Latin name / genitive
- Triangulum Australe / Trianguli Australis
- Position
- Right ascension ≈ 16 h 08 m; declination −70° to −60°
- Visibility from Türkiye
- Not visible from Türkiye; it is observed from the southern hemisphere.
- Best time to observe
- From the southern hemisphere it is best placed around 21:00 in early July.
- Number of stars
- 35 stars brighter than magnitude 6.5 in the catalogue; 6 brighter than 5 and 4 brighter than 4.
INTERACTIVE LAB
Where is Triangulum Australe tonight?
This constellation cannot be seen from Türkiye, so the lab opens for Sydney. Drag the time slider through the southern night, use the “Best night” button to jump to the best date, and switch the city to Ankara to see why it never rises there.
MYTH, HISTORY AND OBSERVING
A distinctive southern constellation of three bright stars, mapped from the observations of Keyser and de Houtman. Its brightest star, Atria, is an orange giant. It is not visible from Türkiye.
BRIGHTEST STARS
| Star | Magnitude | Distance (light-years) | Spectral type |
|---|---|---|---|
| Atria | 1.91 | 391 | K2IIb-IIIa |
| β TrA | 2.83 | 40 | F2III |
| γ TrA | 2.87 | 184 | A1V |
| δ TrA | 3.86 | 607 | G5II |
| ε TrA | 4.11 | 202 | K0III |
| ζ TrA | 4.90 | 40 | F9V |
| HIP 82129 | 5.10 | 697 | Ap |
| κ TrA | 5.11 | 1,208 | G6VII |
Magnitude: apparent brightness; the smaller the number, the brighter the star. Distances derive from parallax measurements and are uncertain for distant stars. Source: HYG v4.1 star catalogue (CC BY-SA 4.0).
SOURCES
Position, visibility and best observing time were computed approximately for this page from the catalogue stars (Ankara, 39.9° N). The 88 constellations were adopted by the IAU in 1922; their boundaries were drawn by Eugène Delporte in 1930.