Constellations
Triangulum constellation
Triangulum is a small ancient constellation already known to Ptolemy. The Greeks called it “Deltoton” because its three stars resemble the Greek capital letter Delta; some also saw in it the island of Sicily. The figure is simple but easy to recognise: a narrow triangle between Andromeda and Aries. Its brightest named star is Mothallah (Alpha Trianguli), although Beta Trianguli actually shines a little brighter. The constellation is famous above all for the Triangulum Galaxy, M33, a spiral galaxy in our Local Group. Under a very dark sky it is considered one of the most distant objects visible to the naked eye at all; in binoculars it is easier. Triangulum stands high in the sky on autumn and early-winter evenings.
The brightest stars in Triangulum
| Star | HIP | Magnitude | Distance | Light set off | Name this star |
|---|---|---|---|---|---|
| β Tri | 10064 | 3.00 | 127 light years | around 1900 | Name this star: β Tri |
| Mothallahα Tri | 8796 | 3.42 | 63 light years | around 1963 | Name this star: Mothallah |
| γ Tri | 10670 | 4.03 | 112 light years | around 1910 | Name this star: γ Tri |
| δ Tri | 10644 | 4.84 | 35 light years | around 1991 | Name this star: δ Tri |
| 6 Tri | 10280 | 4.94 | 291 light years | around 1740 | Name this star: 6 Tri |
| 14 Tri | 11784 | 5.15 | 433 light years | around 1590 | Name this star: 14 Tri |
| 7 Tri | 10559 | 5.25 | 281 light years | around 1750 | Name this star: 7 Tri |
| 10 Tri | 10793 | 5.29 | 377 light years | around 1650 | Name this star: 10 Tri |
| 12 Tri | 11486 | 5.29 | 163 light years | around 1860 | Name this star: 12 Tri |
| 15 Tri | 12086 | 5.38 | 632 light years | around 1390 | Name this star: 15 Tri |
| ε Tri | 9570 | 5.50 | 392 light years | around 1630 | Name this star: ε Tri |
| 11 Tri | 11432 | 5.55 | 278 light years | around 1750 | Name this star: 11 Tri |
| HIP 7943 | 7943 | 5.63 | 275 light years | around 1750 | Name this star: HIP 7943 |
| HIP 8433 | 8433 | 5.78 | 91 light years | around 1935 | Name this star: HIP 8433 |
| HIP 9132 | 9132 | 5.84 | 457 light years | around 1570 | Name this star: HIP 9132 |
Distances from the Hipparcos catalogue. For very distant stars they are uncertain – the year the light set off is therefore only a rough guide.
Frequently asked questions
When can you see the Triangulum constellation?
The best time to see Triangulum is in the evening in November, when the constellation reaches its highest point in the south around 10 pm.
What is the brightest star in Triangulum?
The brightest star in Triangulum is β Tri with an apparent magnitude of 3.00, about 127 light years away.
Can I name a star in Triangulum?
Yes – for free at Sternschenker. Our catalogue contains 25 naked-eye stars in Triangulum. Pick one, give it a name and download your certificate as a PDF. The name is symbolic and not recognised by the IAU.
Which star will it be?
The sky is waiting. Naming your star takes about two minutes.
Name a star in Triangulum