Fornax (the Furnace) is a faint southern constellation introduced by French astronomer Nicolas-Louis de Lacaille in the 18th century. Its brightest star, Dalim, reaches only magnitude 3.9, making Fornax difficult to recognize without a star chart.
Despite its inconspicuous stars, Fornax is one of the most interesting regions of the sky for studying galaxies. It contains the Fornax Cluster, a rich gathering of galaxies approximately 60 million light-years away, as well as a small satellite galaxy of our own Milky Way.
Where Is Fornax and When Can You See It?
Fornax is the 41st-largest constellation, covering approximately 398 square degrees of the southern sky. It is surrounded mainly by the winding constellation Eridanus, with Cetus to the north, Phoenix to the south, and Sculptor to the west.
Fornax is best observed from November through January, particularly from the Southern Hemisphere. Its stars form no distinctive pattern, so observers generally locate it using nearby Eridanus and a detailed star chart.
Who Created the Fornax Constellation?
Fornax was introduced by Nicolas-Louis de Lacaille, who mapped the southern sky while observing from the Cape of Good Hope in South Africa during the 1750s. He originally called the constellation Fornax Chemica, meaning the Chemical Furnace, in recognition of the equipment used by chemists. Its name was subsequently shortened to Fornax.
Unlike the ancient constellations, Fornax has no traditional Greek or Roman mythology. It belongs to Lacaille’s collection of southern constellations named after scientific instruments and other objects.
Notable Stars in Fornax
Although Fornax has no bright first- or second-magnitude stars, several of its stars are scientifically interesting.
- Dalim (Alpha Fornacis) – The constellation’s brightest star, a binary system approximately 46 light-years away with a combined apparent magnitude of 3.9. Its brighter component is a yellow-white subgiant, accompanied by a fainter star in a long-period orbit.
- Beta Fornacis – A yellow giant approximately 170 light-years away, shining at magnitude 4.5. It has expanded and cooled as it evolved beyond the main sequence.
- Nu Fornacis – A blue-white star approximately 370 light-years away, with an apparent magnitude of 4.7. It is considerably hotter and more luminous than the Sun.
- LP 944-20 – A nearby brown dwarf approximately 16 light-years away. Brown dwarfs occupy the mass range between planets and stars and cannot sustain ordinary hydrogen fusion in their cores.
Deep-Sky Objects in Fornax
Fornax contains no Messier objects, but its galaxies make it one of the most rewarding southern constellations for astronomers.
The Fornax Galaxy Cluster
The Fornax Cluster is a large collection of galaxies located approximately 60–65 million light-years from Earth. It is one of the nearest rich galaxy clusters beyond the Local Group and contains dozens of large galaxies alongside many smaller dwarf galaxies. The cluster provides astronomers with an opportunity to study how galaxies interact, lose gas, and evolve within a densely populated environment.
NGC 1399 — A Giant Elliptical Galaxy
NGC 1399 is a massive elliptical galaxy near the center of the Fornax Cluster. Unlike spiral galaxies, it has a smooth, rounded appearance and contains predominantly older stars. It is also surrounded by an exceptionally rich population of globular star clusters.
Its central region hosts a supermassive black hole, while the galaxy’s extended halo provides evidence of its long history of interactions with neighboring galaxies.
NGC 1365 — The Great Barred Spiral Galaxy
NGC 1365 is one of the most striking barred spiral galaxies in the southern sky. Located approximately 55–60 million light-years away, it has a prominent central bar and two sweeping spiral arms containing regions of active star formation.
The galaxy is roughly 200,000 light-years across, making it substantially larger than the Milky Way’s stellar disk. Its central region also contains an active supermassive black hole.
Fornax A (NGC 1316)
Fornax A, also known as NGC 1316, is a large galaxy famous for its powerful radio emission. Its unusual dust lanes and distorted outer structure suggest that it formed through mergers involving other galaxies.
Radio observations reveal enormous lobes of energetic particles extending far beyond the galaxy’s visible stars, powered by activity associated with its central black hole.
The Fornax Dwarf Galaxy
The Fornax Dwarf Spheroidal Galaxy is a small satellite of the Milky Way, located approximately 460,000 light-years away. Unlike the distant Fornax Cluster, it belongs to our own Local Group.
It contains a predominantly old stellar population and several globular clusters, including NGC 1049. Astronomers study the galaxy to investigate dark matter, star formation, and the evolution of smaller galaxies.
How to Find Fornax
Fornax occupies a relatively faint region of sky surrounded by the winding stars of Eridanus. Begin by locating Eridanus, then use a star chart to identify the area enclosed by its southern stretches.
Although the constellation’s stars are difficult to recognize, larger amateur telescopes can reveal some of its brighter galaxies, particularly NGC 1365 and NGC 1399, under dark southern skies.