Octans is located at the South Celestial Pole. It is a circumpolar constellation, so it is visible throughout the year for observers in the Southern Hemisphere.
History and Mythology
Octans is one of the small southern constellations named by Nicholas Louis de Lacaille in 1752 to honor various scientific instruments. This constellation represents the octant, invented by John Hadley and used by Lacaille to measure the positions of the stars. The octant was the forerunner of the sextant.
Notable Objects
Octans consists of a few scattered stars of third magnitude and fainter. The brightest star is Nu Octantis, at magnitude 3.2, and it is the only star brighter than 4th magnitude. Alpha Octantis is a 5.2 magnitude star, 148 light-years away. Beta Octantis is a magnitude 4.3 star, 65 light-years away.
One star of note is Sigma Octantis. This is a 5th magnitude star, and it is within one degree of the South Celestial Pole. Sigma Octantis is the "South Star" marking the southern celestial pole. However, it is 16 times fainter than Polaris, its northern counterpart.
Epsilon Octantis is a semi-regular variable. This pulsating red giant star changes from magnitude 5.0 to 5.4 over a 55-day period.
There are no prominent star clusters or nebulae in Octans. NGC 2573 is a rather faint and obscure galaxy.