|Pronunciation||//, genitive //|
|Area||291 sq. deg. (50th)|
|Stars with planets||3|
|Stars brighter than 3.00m||0|
|Stars within 10.00 pc (32.62 ly)||1|
|Brightest star||ν Oct (3.73m)|
|Visible at latitudes between +0° and −90°.|
Best visible at 21:00 (9 p.m.) during the month of October.
Octans // is a faint constellation located in the deep southern sky. Its name is Latin for the eighth part of a circle, but it is named after the octant, a navigational instrument. The constellation was devised by French astronomer Nicolas Louis de Lacaille in 1752, and it remains one of the 88 modern constellations.
History and mythology
Octans was one of 14 constellations created by Nicolas Louis de Lacaille during his expedition to the Cape of Good Hope, and was originally named "l’Octans de Reflexion", French for “the reflecting octant”. It was part of his catalogue of the southern sky, the Coelum Australe Stelliferum, which was published posthumously in 1763. In Europe, it became more widely known as Octans Hadleianus, in honor of English mathematician John Hadley, who invented the octant in 1730. There is no real mythology related to Octans, partially due to its faintness and relative recentness, but mostly because of its extreme southerly latitude.
Sigma Octantis, the southern pole star, is a magnitude 5.4 star just over 1 degree away from the true South Celestial Pole. Its relative faintness means that it is not practical for navigation. Conveniently for navigators, there are other, much easier methods for locating the southern celestial pole.
For example, the constellation Crux, the Southern Cross, currently points toward the South Celestial Pole, if one draws a line from Gamma Crucis to Alpha Crucis. Another method includes an asterism made up of Sigma, Chi, Tau, and Upsilon Octantis, which form a distinctive trapezoid shape.
- The Deep Photographic Guide to the Constellations: Octans
- Starry Night Photography : Octans
- Star Tales – Octans
|Wikimedia Commons has media related to Octans.|