- Octans was one of 14 new southern constellations introduced in the 1750s by the French astronomer Nicolas Louis de Lacaille. It represents a navigational instrument known as a reflecting octant, invented in 1730 by the Englishman John Hadley (1682–1744). Lacaille originally named it l’Octans de Reflexion on his chart published in 1756, but changed this simply to Octans on the second edition of 1763 on which he Latinized the names of the constellations.