Octans is a constellation in the southern hemisphere, first introduced by the French astronomer Nicolas Louis de Lacaille in the 18th century. Lacaille originally called it l'Octans de Reflexion and later shortened the name to Octans. The constellation represents a reflecting octant, a navigational instrument used to measure the altitude of celestial objects at sea, invented by the English mathematician John Hadley in 1730. In Latin, Octans means "the eighth part of the circle."
The constellation Octans occupies an area of 291 square degrees and contains two stars with known planets. It can be seen at latitudes between +0° and -90° and is best visible at 9 p.m. during the month of October. In southern latitudes, Octans is circumpolar; it never falls under the horizon and can be observed throughout the year.
Octans does not have any bright deep sky objects or stars brighter than fourth magnitude. The brightest star is nu Octantis, an orange giant approximately 64 light-years distant.
Alpha Octantis, a spectroscopic binary star that consists of two giants, is very faint, with a visual magnitude of only 5.15.
Beta Octantis, the second brightest star in the constellation, is a yellow-orange giant.
The most interesting star in the constellation is the faint white giant sigma Octantis, a Delta Scuti type variable star and the nearest star to the South Celestial Pole visible to the naked eye. Because of its proximity to the South Pole, only a degree away, it is also sometimes known as Polaris Australis. Similarly, the star 
delta Octantis is notable for being the southern pole star to the planet Saturn.
Octans belongs to the Lacaille family of constellations, along with Norma
Constellations directly bordering Octans are Tucana