Octans
1061 OBJECTSOctans is one of the 88 constellations the International Astronomical Union uses to divide the sky, a region in the far south, about 28 degrees across. Its boundary is a fixed line rather than a picture, so anything inside it belongs to it whether or not it forms part of the figure the name refers to. This catalogue holds 1061 objects there.
Octans holds 1061 catalogued objects: 807 stars, 227 galaxies, 23 exoplanets, 4 neutron stars.
[
BRIGHTEST OBJECTS
] 12 SHOWNNAME
CLASS
MASS
DISTANCE
MAG
CONSTELLATION
ν Oct
K1III orange giant
—
69.14 ly
3.73 V
Octans
β Oct
A9IV/V white subgiant
—
149.3 ly
4.13 V
Octans
δ Oct
K2III orange giant
—
299.0 ly
4.31 V
Octans
θ Oct
K3III orange giant
—
217.1 ly
4.78 V
Octans
ε Oct
M5III red giant
—
290.7 ly
5.09 V
Octans
γ¹ Oct
G6/8III yellow giant
~2.79 M☉
265.2 ly
5.10 V
Octans
α Oct
F6(m)pec yellow-white star
~1.81 M☉
142.0 ly
5.13 V
Octans
λ Oct
G8/K0III yellow giant
—
409.2 ly
5.27 V
Octans
χ Oct
K3III orange giant
—
256.8 ly
5.29 V
Octans
γ³ Oct
K1/2III orange giant
~3.00 M☉
254.6 ly
5.29 V
Octans
ξ Oct
B6V blue-white main-sequence star
—
492.7 ly
5.32 V
Octans
ζ Oct
A8/9IV white subgiant
—
162.3 ly
5.43 V
Octans
[
COMMON QUESTIONS
] 8 ANSWERED- Where in the sky is Octans?
- Its boundary is centred near right ascension 22h 45m, declination −84.5°. It stands at its highest around midnight in late August, which puts it in the evening sky for the two months after that and behind the Sun half a year later.
- Can I see it from where I live?
- Every part of Octans clears the horizon from latitudes between the south pole and the equator. Outside that band some or all of the region never rises at all, whatever the time of year — a constellation is fixed on the sky, and it is your latitude that decides how much of the sky you get.
- What is the brightest thing in it?
- The brightest catalogued object in Octans is ν Oct, at apparent magnitude 3.73 (V). That is apparent brightness — how it looks from Earth — so it mixes how much light a thing gives off with how far away it is, and the brightest object in a region is rarely the most interesting one.
- How are the stars in it named?
- The brightest carry Greek letters, assigned roughly in order of brightness — by Johann Bayer in 1603, and for the deep southern constellations by Nicolas-Louis de Lacaille in the 1750s — followed by the Latin genitive of the constellation's name. Fainter naked-eye stars north of about −30° take a number from John Flamsteed's catalogue, which never covered the far south, and fainter still a designation from whichever survey recorded them.
- What exactly are the boundaries?
- Lines of constant right ascension and declination, drawn by Eugène Delporte for the IAU in 1930 and referred to the sky as it stood in 1875. Precession has tilted the sky against them since, which is why the boundaries on a modern chart are very slightly askew.
- Are the stars in Octans actually near each other?
- Almost never. The stars in a constellation lie at wildly different distances and are not related to one another in any way — the pattern is a line of sight from one particular planet. Two stars that look adjacent can be a hundred times further apart than either is from the Sun.
- What is the difference between a constellation and an asterism?
- A constellation is one of the 88 regions the IAU recognises, with a fixed boundary and an official name. An asterism is any memorable pattern that is not one — the Plough inside Ursa Major, the Summer Triangle drawn across three constellations, the Great Square shared between two.
- Why are the names in Latin?
- Because the list was assembled in Latin. Fifty of the 88 descend from Ptolemy's second-century catalogue of forty-eight — his ship Argo was later cut into three — and the rest were coined between the sixteenth and eighteenth centuries to fill the southern sky and the gaps. The genitive form is what star names use: Alpha Orionis means the alpha star of Orion.