Achernar: how to find it and when to see it
Achernar ranks 9th of the 74 bright stars on our list, at magnitude 0.45, in the constellation Eridanus.
You can see it from anywhere south of 33° N, and it's highest in the evening sky in November.
Achernar at a glance
- Constellation
- Eridanus
- Magnitude
- 0.45
- Rank on our list
- 9 of 74
- Hemisphere
- Southern
- Right ascension
- 1 h 38 min
- Declination
- 57.2° south
- Visible from
- south of 33° N
- Never sets
- south of 33° S
- Best evening
- November 30
- Name from
- Arabic
Where Achernar is in the sky
Achernar sits 57.2° south of the celestial equator, the line in the sky directly above Earth's equator, so it's in the southern half of the sky. Its right ascension is 1 h 38 min.
Right ascension works like longitude on the sky. It's counted in hours, and about one hour of it turns past you each hour of the night.
When and where to see Achernar
From the northern hemisphere
From 40° N, the latitude of New York, Madrid and Beijing, Achernar never rises above the horizon. You need to be south of 33° N to see it.
From the southern hemisphere
From 34° S, the latitude of Sydney, Cape Town and Buenos Aires, Achernar never sets: it circles the pole all night and climbs to 67° above the horizon in the south.
It's in the evening sky from August to March, and it's highest in the evening around November 30, in spring.
How high Achernar climbs from each latitude
The evening is about 9 pm local time, or 10 pm in summer time, and later when the sky is still too bright. A star counts as in the evening sky when it's at least 10° above the horizon.
| Latitude | Visibility | Highest point | Evening sky |
|---|---|---|---|
| 60° N | Never rises | Below the horizon | None |
| 50° N | Never rises | Below the horizon | None |
| 40° N | Never rises | Below the horizon | None |
| 30° N | Rises and sets | 3° in the south | None |
| 20° N | Rises and sets | 13° in the south | Nov to Dec |
| Equator | Rises and sets | 33° in the south | Oct to Jan |
| 20° S | Rises and sets | 53° in the south | Sep to Feb |
| 34° S | Never sets | 67° in the south | Aug to Mar |
| 45° S | Never sets | 78° in the south | All year |
What the name Achernar means
Achernar comes from the Arabic ākhir al-nahr, the end of the river. It marks the southern end of Eridanus, the river constellation.
Keep the sky of a night that matters
Our star maps show the stars above any place, at the minute you choose, with the constellation lines drawn in. If Achernar was above the horizon that night, it's on your map, and we print it on museum-grade paper.
Questions about Achernar
Achernar is in Eridanus. It sits 57.2° south of the celestial equator, at a right ascension of 1 h 38 min.
Achernar is highest in the evening sky around November 30. That's autumn in the northern hemisphere and spring in the southern hemisphere.
Yes, from anywhere south of 33° N. From 40° N, it never rises, so you need to be further south.
Achernar has a magnitude of 0.45, which ranks it 9th of the 74 bright stars on our list. Sirius looks about 5.7 times brighter.
Achernar comes from the Arabic ākhir al-nahr, the end of the river. It marks the southern end of Eridanus, the river constellation.