Constellation · Southern sky · Fall

Octans, the Octant

OK-tanz · genitive Octantis · Oct

The constellation of the south celestial pole, named for the navigator's octant. Unlike the north, the south has no bright pole star: σ Octantis, the nearest naked-eye star to the pole, is barely magnitude 5.4.

0h 6h 12h 18h
Where Octans sits on the whole sky. Gold line: the ecliptic.
Octans star chart with deep-sky objects HYDRUS MENSA Sigma Octantis | Variable star | mag 5.4 σ Oct Polarissima Australis | Galaxy | mag 13.5 NGC 2573 NE

Swipe sideways to pan the chart.

Stars to magnitude 8, IAU boundary and stick figure, J2000. Click any object to open its page; click a neighboring constellation's name to go there. Nebula Open cluster Galaxy Planetary nebula Dark nebula Double star
Area
292 sq°rank 50 of 88
Best month
Octoberat 9 pm
Visible from
0° to 90°S
Brightest star
ν Oct (mag 3.73)
Messier
0none
Caldwell
0none
Cataloged objects
119in 7 catalogs

Finding the south celestial pole

Octans has no bright stars. Southern observers find the pole by star-hopping.

  • From the Southern Cross: extend the long axis of the Cross, Gacrux through Acrux, about 4.5 times its length.
  • Between Achernar and the Cross: the pole lies roughly halfway between Achernar and the Southern Cross.
  • σ Octantis: a faint star about 1° from the pole, at the top of a small trapezoid with χ, τ and υ Oct.

Always above the horizon from the Southern Hemisphere

Octans is circumpolar from all southern latitudes and never rises from the Northern Hemisphere. Its stars are best placed at 9 pm in October.

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 60°N JAN at 60°N: -60° high at 9 pm FEB at 60°N: -63° high at 9 pm MAR at 60°N: -65° high at 9 pm APR at 60°N: -66° high at 9 pm MAY at 60°N: -64° high at 9 pm JUN at 60°N: -62° high at 9 pm JUL at 60°N: -59° high at 9 pm AUG at 60°N: -56° high at 9 pm SEP at 60°N: -55° high at 9 pm OCT at 60°N: -54° high at 9 pm NOV at 60°N: -55° high at 9 pm DEC at 60°N: -57° high at 9 pm 50°N JAN at 50°N: -50° high at 9 pm FEB at 50°N: -53° high at 9 pm MAR at 50°N: -55° high at 9 pm APR at 50°N: -56° high at 9 pm MAY at 50°N: -55° high at 9 pm JUN at 50°N: -52° high at 9 pm JUL at 50°N: -49° high at 9 pm AUG at 50°N: -46° high at 9 pm SEP at 50°N: -45° high at 9 pm OCT at 50°N: -44° high at 9 pm NOV at 50°N: -45° high at 9 pm DEC at 50°N: -47° high at 9 pm 40°N JAN at 40°N: -40° high at 9 pm FEB at 40°N: -43° high at 9 pm MAR at 40°N: -45° high at 9 pm APR at 40°N: -46° high at 9 pm MAY at 40°N: -45° high at 9 pm JUN at 40°N: -42° high at 9 pm JUL at 40°N: -39° high at 9 pm AUG at 40°N: -36° high at 9 pm SEP at 40°N: -35° high at 9 pm OCT at 40°N: -34° high at 9 pm NOV at 40°N: -35° high at 9 pm DEC at 40°N: -38° high at 9 pm 30°N JAN at 30°N: -31° high at 9 pm FEB at 30°N: -33° high at 9 pm MAR at 30°N: -35° high at 9 pm APR at 30°N: -36° high at 9 pm MAY at 30°N: -35° high at 9 pm JUN at 30°N: -32° high at 9 pm JUL at 30°N: -29° high at 9 pm AUG at 30°N: -27° high at 9 pm SEP at 30°N: -25° high at 9 pm OCT at 30°N: -24° high at 9 pm NOV at 30°N: -25° high at 9 pm DEC at 30°N: -28° high at 9 pm 20°N JAN at 20°N: -21° high at 9 pm FEB at 20°N: -23° high at 9 pm MAR at 20°N: -25° high at 9 pm APR at 20°N: -26° high at 9 pm MAY at 20°N: -25° high at 9 pm JUN at 20°N: -22° high at 9 pm JUL at 20°N: -19° high at 9 pm AUG at 20°N: -17° high at 9 pm SEP at 20°N: -15° high at 9 pm OCT at 20°N: -14° high at 9 pm NOV at 20°N: -15° high at 9 pm DEC at 20°N: -18° high at 9 pm 10°N JAN at 10°N: -11° high at 9 pm FEB at 10°N: -13° high at 9 pm MAR at 10°N: -15° high at 9 pm APR at 10°N: -16° high at 9 pm MAY at 10°N: -15° high at 9 pm JUN at 10°N: -12° high at 9 pm JUL at 10°N: -9° high at 9 pm AUG at 10°N: -7° high at 9 pm SEP at 10°N: -5° high at 9 pm OCT at 10°N: -4° high at 9 pm NOV at 10°N: -5° high at 9 pm DEC at 10°N: -8° high at 9 pm 0° JAN at 0°: -1° high at 9 pm FEB at 0°: -3° high at 9 pm MAR at 0°: -5° high at 9 pm APR at 0°: -6° high at 9 pm MAY at 0°: -5° high at 9 pm JUN at 0°: -2° high at 9 pm JUL at 0°: 1° high at 9 pm AUG at 0°: 3° high at 9 pm SEP at 0°: 5° high at 9 pm OCT at 0°: 6° high at 9 pm NOV at 0°: 5° high at 9 pm DEC at 0°: 2° high at 9 pm 10°S JAN at 10°S: 9° high at 9 pm FEB at 10°S: 6° high at 9 pm MAR at 10°S: 5° high at 9 pm APR at 10°S: 4° high at 9 pm MAY at 10°S: 5° high at 9 pm JUN at 10°S: 8° high at 9 pm JUL at 10°S: 10° high at 9 pm AUG at 10°S: 13° high at 9 pm SEP at 10°S: 15° high at 9 pm OCT at 10°S: 16° high at 9 pm NOV at 10°S: 15° high at 9 pm DEC at 10°S: 12° high at 9 pm 20°S JAN at 20°S: 19° high at 9 pm FEB at 20°S: 16° high at 9 pm MAR at 20°S: 15° high at 9 pm APR at 20°S: 14° high at 9 pm MAY at 20°S: 15° high at 9 pm JUN at 20°S: 18° high at 9 pm JUL at 20°S: 20° high at 9 pm AUG at 20°S: 23° high at 9 pm SEP at 20°S: 25° high at 9 pm OCT at 20°S: 26° high at 9 pm NOV at 20°S: 25° high at 9 pm DEC at 20°S: 22° high at 9 pm 30°S JAN at 30°S: 29° high at 9 pm FEB at 30°S: 26° high at 9 pm MAR at 30°S: 25° high at 9 pm APR at 30°S: 24° high at 9 pm MAY at 30°S: 25° high at 9 pm JUN at 30°S: 28° high at 9 pm JUL at 30°S: 30° high at 9 pm AUG at 30°S: 33° high at 9 pm SEP at 30°S: 35° high at 9 pm OCT at 30°S: 36° high at 9 pm NOV at 30°S: 35° high at 9 pm DEC at 30°S: 32° high at 9 pm 40°S JAN at 40°S: 39° high at 9 pm FEB at 40°S: 36° high at 9 pm MAR at 40°S: 35° high at 9 pm APR at 40°S: 34° high at 9 pm MAY at 40°S: 35° high at 9 pm JUN at 40°S: 37° high at 9 pm JUL at 40°S: 40° high at 9 pm AUG at 40°S: 43° high at 9 pm SEP at 40°S: 45° high at 9 pm OCT at 40°S: 46° high at 9 pm NOV at 40°S: 45° high at 9 pm DEC at 40°S: 42° high at 9 pm below horizon low 20-40° 40-60° overhead-ish
Altitude of the constellation's center at 9 pm local time on the 15th of each month. Computed from its position, for any longitude.

Octans's targets are the pole and faint galaxies

Octans has no Messier or Caldwell objects.

Best targets
ObjectTypeMagSizeDistanceBest with
Sigma Octantisσ Oct · Polaris AustralisVariable star5.4star270 lyNaked eye
Polarissima AustralisNGC 2573Galaxy13.51.9′~98 million lyTelescope
OCTANS

On each object page: a locator like this one shows where Sigma Octantis sits in Octans. The box marks a 2.5° field, about what 10×50 binoculars show.

Turned sideways: ν Oct is 69 light-years away, σ Oct 270

ν Oct is 69 light-years away, β Oct 149 and σ Oct about 270. NGC 2573 is about 100 million light-years away.

Octans turned sideways: how far away each star and object is STARS YOU CAN SEE MILKY WAY OTHER GALAXIES 10 ly 100 ly 1,000 ly 10,000 ly 100,000 ly 1 million ly 10 million ly 100 million ly EARTH ν Oct: 69 lyν Oct69 ly β Oct: 149 lyβ Oct149 ly δ Oct: 300 lyδ Oct300 ly θ Oct: 211 lyθ Oct211 ly ε Oct: 293 lyε Oct293 ly γ1 Oct: 268 lyγ1 Oct268 ly α Oct: 147 lyα Oct147 ly λ Oct: 408 lyλ Oct408 ly γ3 Oct: 264 lyγ3 Oct264 ly χ Oct: 261 lyχ Oct261 ly Sigma Octantis: 270 lySigma Octantis270 ly Polarissima Australis: ~98 million lyPolarissima Australis~98 million ly
Side view: distance from Earth on a logarithmic scale, each step ten times farther. The vertical position of every star and object is unchanged. Stick-figure lines join only stars with measured distances.

Brightest stars in Octans

StarDesignationMagDistanceSpectral class
ν Octν Oct3.7369 lyK0III
β Octβ Oct4.13149 lyA9IV/V
δ Octδ Oct4.31300 lyK2III
θ Octθ Oct4.78211 lyK2III
ε Octε Oct5.09293 lyM6III
γ1 Octγ1 Oct5.10268 lyG7III
α Octα Oct5.13147 lyF4III
λ Octλ Oct5.27408 lyG8/K0III+
χ Octχ Oct5.29261 lyK3III
γ3 Octγ3 Oct5.29264 lyK1/K2III

Every cataloged object in Octans

The table above is the short list. Below is everything the major catalogs place inside the IAU boundary of Octans. Open a catalog to see its brightest members. Each list shows up to 25; longer lists link to the full catalog page.

NGC9
DesignationNameTypeMagDistance
NGC 7098galaxy11.5110.4 million ly
NGC 6438galaxy11.6-
NGC 6920galaxy11.9-
NGC 7095galaxy11.9119.4 million ly
NGC 2573Polarissima Australisgalaxy13.597.7 million ly
NGC 2573Bgalaxy-
NGC 6438Agalaxy-
NGC 6557galaxy158.9 million ly
NGC 7637galaxy-
IC8
DesignationNameTypeMagDistance
IC 4864galaxy13.5-
IC 4333galaxy-
IC 4912galaxy232.3 million ly
IC 4928galaxy-
IC 5022galaxy-
IC 5025galaxy257.1 million ly
IC 5026galaxy113.8 million ly
IC 5040galaxy-
Open clusters1
DesignationNameTypeMagDistance
Melotte 227not confirmed5.3-
Arp-Madore galaxies7
DesignationNameTypeMagDistance
AM 1806-852 NED0111.6118.4 million ly
AM 1806-852 NED0211.6118.4 million ly
AM 2036-801 NED0111.9122 million ly
AM 2145-81411.9119.4 million ly
AM 203-841165 million ly
AM 2217-801122 million ly
AM 2322-821174 million ly
Abell galaxy clusters74
DesignationNameTypeMagDistance
Abell S1014S315.5529 million ly
Abell S21S116.1-
Abell S800S216.2-
Abell S107S116.2-
Abell S810S216.6997 million ly
Abell S787S216.6-
Abell S1131S316.6-
Abell 3624816.8-
Abell S791S216.8-
Abell S949S216.9-
Abell S1061S316.9-
Abell 3741817.0-
Abell S926S217.0-
Abell S788S217.0-
Abell S785S217.0-
Abell 3626817.0-
Abell S605S217.1-
Abell 2793617.1-
Abell S1091S317.1-
Abell 3595817.1-
Abell S995S217.1-
Abell 3728817.11,320 million ly
Abell S389S117.1-
Abell 3631817.1-
Abell S480S117.1-
The 25 brightest of 74 in Octans
Exoplanets2
DesignationNameTypeMagDistance
Nu Octantis A b3.7369 ly
HD 221420 b5.82102 ly
Nearby stars (Gliese)18
DesignationNameTypeMagDistance
Gl 835.1Nu Octanis73.7369 ly
NN 434085.82102 ly
Gl 67.115.8888 ly
Gl 606.1A67.70112 ly
NN 4229A78.2377 ly
NN 431789.9673 ly
Gl 385410.21974 ly
Gl 877810.4228 ly
NN 4230B710.5077 ly
Gl 606.1B611.03112 ly
NN 4154711.5035 ly
Gl 808711.8556 ly
NN 3486312.5586 ly
NN 4102712.7041 ly
Gl 820.1713.5653 ly
GJ 1251713.8242 ly
NN 4045614.1070 ly
NN 3958614.585,136 ly

A planet in a tight binary

  • ν Octantis. A tight binary star with a planet that appears to orbit backward, opposite to the stars' own orbit; a 2025 study supported this unusual arrangement.

Octans video tour

Octans Constellation: Best deep sky objects · Watch on YouTube

A navigator's octant

Nicolas-Louis de Lacaille named Octans in the 1750s for the reflecting octant invented by John Hadley, the instrument navigators used to measure star altitudes at sea.

Constellations bordering Octans

Octans shares its IAU boundary with 7 constellations.