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The Octant

Constellation of the southern sky

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Constellation FamilyLa Caille
Celestial QuadrantSQ1, SQ2, SQ3, SQ4
Right AscensionCircumpolar
Declination-75.4° to -90.0°
Area (sq deg)291
Brightest StarNu Octantis
Optimum VisibilityAlways visible from southern latitudes
NotesThe polar constellation of Octans contains the Southern Celestial Pole, and thus always lies southward of the observer. Unlike its northern equivalent of Ursa Minor, however, Octans contains no stars brighter than fourth magnitude, and no feature like Polaris in the north that might help to fix the exact position of the pole.
Map of Octans Map of Octans
Relative Galactic Position of Octans

Octans' place in the galaxy. Because Octans contains the Southern Celestial Pole, this diagram also shows the Earth's orientation with respect to the galaxy as a whole.

The Southern Celestial Pole lies in Octans, just as the Northern Celestial Pole lies in Ursa Minor. Unlike Polaris in the north, though, no bright star lies near the Southern Pole. This hasn't prevented the star Sigma Octantis being rather optimistically named 'Polaris Australis' or 'The Southern Pole Star', but it is in fact only magnitude +5.5, and almost invisible to the naked eye.


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