Constellation, Altar
Ara
The altar on which the gods of Greek myth swore an alliance before their war against the Titans. Old star maps draw it as a censer with its flames rising southwards.
From New York the constellation Ara never rises above the horizon: it belongs to the other hemisphere’s sky.
From New York the constellation Ara never rises above the horizon: it belongs to the other hemisphere’s sky.
In the 3D sky
The sky over New York turned towards Ara. Drag to look around.
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Evening visibility over the year
Height of the constellation’s centre above the horizon at 10 pm local time on the 15th of each month, from New York. Above about 30° it is well placed.
Name and history
According to Eratosthenes and Manilius, the gods of Olympus swore an oath of allegiance on this altar before they fought the Titans. Zeus had freed his brothers and sisters from their father Cronus, and the gods vowed to end the rule of the Titans. After their victory Zeus placed the altar in the sky in gratitude. The Greek name, Thymiaterion, means an incense burner or censer.
Ptolemy described the altar with its base to the north and its flames rising southwards, and most star maps follow him. Even the Farnese globe of the second century shows it facing south. Some atlases make it the altar on which Centaurus is about to sacrifice the wolf, Lupus. The Greek letters used today for its stars were given by Lacaille in 1763. In China five of its stars formed a turtle living in the river of the Milky Way.
Sources: Ian Ridpath, Star Tales: Ara
Brightest stars
| Star | Designation | Magnitude | Distance |
|---|---|---|---|
| β Ara | β Ara | 2.84 | 646 light-years |
| α Ara | α Ara | 2.84 | 267 light-years |
| ζ Ara | ζ Ara | 3.12 | 486 light-years |
| γ Ara | γ Ara | 3.31 | 1,113 light-years |
| δ Ara | δ Ara | 3.60 | 198 light-years |
| θ Ara | θ Ara | 3.65 | 813 light-years |
| η Ara | η Ara | 3.77 | 299 light-years |
| ε1 Ara | ε1 Ara | 4.06 | 361 light-years |
| σ Ara | σ Ara | 4.56 | 378 light-years |
| λ Ara | λ Ara | 4.76 | 70 light-years |
Facts
| Area | about 238 square degrees (63 of 88) |
|---|---|
| IAU abbreviation | Ara |
| Sky | Southern sky |
| Origin | Listed in Ptolemy’s Almagest, about AD 150, and described by Aratus before him |
| Stars brighter than magnitude 5 | 10 |
| Centre (J2000) | 17.4 h, -54° |
Deep-sky objects
Galaxies, clusters and nebulae brighter than magnitude 9, from the OpenNGC catalogue. Most need binoculars or a telescope and a dark sky.
| Object | Type | Magnitude |
|---|---|---|
| NGC6397 | Globular cluster | 5.2 |
| NGC6250 | Cluster with nebula | 5.9 |
| IC4651 | Open cluster | 6.9 |
| NGC6208 | Open cluster | 7.2 |
| NGC6200 | Open cluster | 7.4 |
| NGC6204 | Open cluster | 8.2 |
| NGC6362 | Globular cluster | 8.9 |
| NGC6352 | Globular cluster | 8.9 |
Boundaries: International Astronomical Union, via Astronomy Engine. Areas are computed from the boundaries by sampling (within about one percent). Names and lines: Stellarium. Stars: HYG Database. Deep-sky objects: OpenNGC. Calculated with Astronomy Engine, an open-source library verified against the US Naval Observatory and NASA JPL. Data sources
How to use this page
Choose your place and a night at the top. The answer and the 3D view show where the constellation is, when it is highest and whether it rises at all from where you are. The chart shows its stars and lines, and the tables list its brightest stars and the deep-sky objects inside it.
Frequently asked questions
When is a constellation best seen?
When it is highest in a dark sky, which the page gives for the night you pick. Each constellation is best placed in a particular season, because the stars rise about four minutes earlier every night.
Why can I not see a constellation from my place?
Constellations far south of the celestial equator never rise from northern places, and those far north never rise from southern ones. The page says when this is the case.
What are the constellation boundaries?
The International Astronomical Union divides the sky into 88 areas with official boundaries. The stick figures are only a drawing aid, the boundaries say which constellation a point in the sky belongs to.
Related guides
- How to learn the constellationsStart with one bright pattern you cannot miss, use it as a signpost to its neighbours, and come back a month later: the sky will have turned, and you will know a little more of it.
- Altitude and azimuth: finding things in the skyTwo angles tell you exactly where to look: which direction, and how high.
- Light pollution and dark skies: the Bortle scaleFrom a city centre you can count a few dozen stars. From a truly dark site you can count a few thousand, with the Milky Way bright enough to cast a shadow. The Bortle scale puts a number on the difference.
- Binoculars for stargazing: what to buy and what to look atA pair of 7x50 or 10x50 binoculars shows the craters of the Moon, the moons of Jupiter, dozens of star clusters and the Andromeda Galaxy, for a fraction of the cost of a telescope.