Triangulum Australe
TrA · genitive Trianguli Australis · southern sky
At a glance
- Catalogued stars
- 35
- Visible to the eye
- 35 stars
- Brightest star
- Atria (1.91)
- Best seen
- May
- Declination span
- -69.0° to -63.4°
- Nearest star
- Zet TrA · 39.5 ly
Visible from everywhere south of about 21°N.
When and where to look for Triangulum Australe
Triangulum Australe crosses the meridian — its highest point in the sky — at local midnight around May, which makes the months from April to June the easiest time to find it in the evening. It spans declinations -69.0° to -63.4°, so visible from everywhere south of about 21°N.
The quickest way to find it is to open the live AR sky map and point your phone at the sky — if Triangulum Australe is above your horizon right now, its figure is drawn in the position it genuinely occupies above you.
Brightest stars in Triangulum Australe
| Star | Mag | Type | Distance |
|---|---|---|---|
| AtriaAlp TrA | 1.91 | K2IIb-IIIa | 390.6 ly |
| Bet TrA | 2.83 | F2III | 40.4 ly |
| Gam TrA | 2.87 | A1V | 183.9 ly |
| Del TrA | 3.86 | G5II | 607.4 ly |
| Eps TrA | 4.11 | K0III | 201.7 ly |
| Zet TrA | 4.90 | F9V | 39.5 ly |
Magnitude runs backwards: lower numbers are brighter, and anything below about 6.5 is beyond the naked eye under a dark sky.
What Triangulum Australe is made of
The catalogue lists 35 stars within Triangulum Australe, of which 35 are magnitude 6.5 or brighter — the limit of what an unaided eye picks up under a genuinely dark sky. The rest need binoculars or a telescope.
Spectral make-up
Spectral class is a temperature ordering, running from O at around 30,000 K down to M below 3,500 K. A constellation is a direction, not a group, so this is simply what happens to lie along that line of sight.
The closest catalogued star in this direction is Zet TrA at 39.5 light years. The most distant is HD 150097 at roughly 1,615 light years — stars that appear side by side here are nothing of the sort.