Octans Constellation: The Ultimate Guide

Octans is one of the 88 modern constellations. It has no associated history in ancient Western cultures because it was not visible in those regions.

Octans is one of the faintest constellations. Most of its stars cannot be seen with the naked eye, so it was necessary to wait for telescopes to be invented to see them.

Octans was one of the 14 constellations created by the French astronomer Nicolas Louis de Lacaille during his expedition to the Cape of Good Hope in 1752 and was initially called l'Octans de Reflexion ("the reflective octant").

Lacaille devised fourteen new constellations in unexplored regions of the Celestial Southern Hemisphere that were not visible from Europe. All the new constellations honored instruments that symbolized the Age of Inventions.

Originally Octans was part of his catalog of the southern sky, the Coelum Australe Stelliferum, published posthumously in 1763.

In Europe, it became better known as Octans Hadleianus in honor of the English mathematician John Hadley, who invented the octant in 1730. Later, cartographers began to call it only by its first name Octans.

In 1922 the International Astronomical Association added the constellation Octans to the 88 official night sky constellations. Since then, it has not undergone modifications in its boundaries or name.

Thus Octans is one of the minor constellations as it occupies a total area of only 291 square degrees. This places it 50th in size among the 88 constellations in the night sky.

Octans reside in the fourth quadrant of the Southern Hemisphere (SQ4) between latitudes 0° N and 90° S.

Octans is visible in South America, Africa, Australia, and Antarctica.

Octans are not visible in any Northern Hemisphere region; this includes the US, Europe, Russia, China, or Japan.

Octans is a constellation very close to the south pole. It is visible all year round; however, October is the best month to visualize it.

The constellation Octans is not visible in the Northern Hemisphere in any season. While in the southern hemisphere, it is visible throughout the fall and early winter.

People living in the northern hemisphere cannot locate this constellation in the sky.

In addition, Octans is a constellation without stars of the first or second magnitude, so it is too faint to find with the naked eye; you can support yourself using the star Beta Hydri of the constellation Hydrus.

The easiest way to locate the constellation Octans is by drawing an imaginary straight line from the star Beta Hydri of the constellation Hydrus towards the star Atria of the constellation Triangulum Australe. Octans is located halfway there.

The constellations bordering Octans are Tucana, Indus, Pavo, Apus, Chamaeleon, Mensa, and Hydrus.

In addition, Octans belongs to the Lacaille family of constellations; these include Antlia, Caelum, Circinus, Fornax, Horologium, Mensa, Microscopium, Norma, Pictor, Reticulum, Sculptor, and Telescopium.

The constellation Octans officially contains 60 stars, of which 6 form the central figure of the constellation; these are Nu Octantis, Beta Octantis, Delta Octantis, Theta Octantis, Epsilon Octantis, and Polaris Australis.

It is the brightest star in the constellation Octans, with an apparent magnitude of +3.73. It is 69 light-years away from the Solar System.

It is an orange giant of species type K1III. Its parameters are modest in the case of a giant star: its luminosity is 16 times greater than that of the Sun, and its radius is 5.9 times larger.

It is called Polaris Australis because it is the polar star of the southern hemisphere, the equivalent of Polaris in the northern hemisphere. However, unlike this one, Polaris Australis is a faint star of apparent magnitude +5.42, barely visible to the naked eye.

Two hundred seventy light-years from the solar system, Polaris Australis is classified as a white giant star of spectral type F0III, with a surface temperature of 7460 K.

Octans is also home to a couple of deep-sky objects. Deep-sky objects often mean star clusters, nebulae (interstellar cloud bodies), or galaxies.

In the case of Octans, because it is a small constellation and has very few deep-sky objects, the most notable is NGC 7098.

It is a double-barred spiral galaxy located about 95 million light-years away from Earth in the constellation of Octans, this has an estimated diameter of 152,400 light-years, so it is larger than the Milky Way.

NGC 7098 has a very prominent bar with an overall oval shape with very prominent edges that provide it with excellent brightness. However, NGC 7098 has an apparent magnitude of 11.3, making it difficult to see even with telescopes.

• Octans is a constellation located primarily in the southern hemisphere. Its name comes from the Latin "Octante" and represents the eighth part of a circle; in ancient times, the Octante was an instrument that cartographers used to measure constellations.
• The constellation Octans lies between latitudes 0° N and 90° S. The best month to observe the constellation is in October.
• The easiest way to locate the constellation Octans is by drawing an imaginary straight line from the star Beta Hydri of the constellation Hydrus towards the star Atria of the constellation Triangulum Australe. Octans is located halfway there.
• The brightest star in the constellation Octans is Nu Octantis (ν Oct/HD 205478/HR 8254) with an apparent magnitude of +3.73.
• The most notable deep-sky body in the constellation Octans is the galaxy NGC 7098.

1. https://www.constellation-guide.com/constellation-list/octans-constellation/
2. http://www.seasky.org/constellations/constellation-octa ns.html
3. https://www.britannica.com/place/Octans
4. https://www.universeguide.com/constellation/octans
5. https://in-the-sky.org/data/constellation.php?id=59