Reticulum
“The Reticle” · Southern · best around January evenings
Real star positions and magnitudes (HYG database via D3-Celestial, BSD-3). Lines are the conventional stick figure; north is up.
The story
Lacaille's eyepiece crosshairs — the tiny diamond he used to measure the very stars he was naming. Zeta Reticuli, a nearby pair of sun-like stars, is a fixture of UFO folklore (the science: two ordinary G dwarfs).
How to find it
Between Achernar and Canopus.
✦ What lives inside it
- Zeta Reticuli solar twins
The deep dive
Researched for the Atlas from Wikipedia — Reticulum (2,893 characters read) · updated Sep 20, 2026
01 A name born from telescope crosshairs
Most constellation names honor mythological figures or animals, but Reticulum commemorates a piece of laboratory equipment. Nicolas Louis de Lacaille named it le Réticule Rhomboide while working at the Cape of Good Hope in the eighteenth century, specifically to honor the reticle — the grid of fine crosshairs placed at the focus of a telescope eyepiece — that he relied on to measure star positions with precision. It was a practical astronomer's tribute to a practical tool. Lacaille later Latinized the name to Reticulum when he published his southern star catalogue, Coelum Australe Stelliferum. The word itself derives from the Latin for a small net, which is exactly what a reticle looks like when you peer through an eyepiece: a delicate web of lines imposed on the sky to help pin down where things actually are.
02 From Rhombus to Columbus — a rejected reinvention
Before Lacaille stamped his authority on this patch of sky, the area already had a predecessor constellation. In 1621, Isaac Habrecht II introduced a figure he called Rhombus on his celestial globe, describing a shape that loosely corresponded to the same stars. Lacaille replaced it with his somewhat differently drawn Réticule Rhomboide, preserving the rhombus theme in the subtitle while shifting the concept entirely toward instrument-worship. Then in 1810, the American astronomer William Croswell tried yet another reinvention: he reused the stars of Reticulum to draw Marmor Sculptile, meant to represent the bust of Christopher Columbus. It was an ambitious patriotic gesture, but astronomers simply ignored it, and the proposal vanished from the literature without leaving a lasting mark. Lacaille's version, eventually ratified by the International Astronomical Union at its First General Assembly in 1922, was the one that stuck.
03 How the IAU drew the borders in 1875 Deeper
When the International Astronomical Union formally recognized Reticulum in 1922, the constellation still lacked precisely defined borders. That task fell to the Belgian astronomer Eugène Delporte, who drafted boundaries for Reticulum and all the other constellations by drawing arcs strictly along lines of right ascension and declination, anchored to the celestial coordinates of the epoch 1875. Using a fixed epoch rather than the current date was a deliberate choice: it meant every boundary was a clean, reproducible grid line rather than a curve that drifted with time. Delporte's work was published in 1930 in the Delimitation Scientifique des Constellations, issued at the IAU's request. Because Earth's rotational axis slowly wobbles — a motion called precession — those 1875 grid lines no longer align perfectly with modern coordinate systems, but the boundaries themselves remain the official ones used in every star atlas today.
04 Alpha and Beta: the constellation's only bright stars
Reticulum is genuinely sparse when it comes to naked-eye stars. Only two members of the constellation shine brighter than visual magnitude 5: Alpha Reticuli and Beta Reticuli. Alpha is notable enough that the International Astronomical Union assigned it the proper name Rhombus, approved on 19 September 2024 — a nod stretching all the way back to Habrecht's 1621 constellation of the same name. Lacaille himself gave ten stars in the constellation Bayer designations, labeling them Alpha through Iota in 1756, and he also labeled two separate stars as Zeta. The astronomer Benjamin Gould later added Kappa Reticuli in 1879, judging the star bright enough to deserve a formal Greek-letter designation. The constellation's dimness is the main reason it remains invisible from any location north of the 30th parallel north, and even from ideal southern sites, only Alpha clears the threshold of easy naked-eye visibility under less-than-perfect skies.
05 R Reticuli: a star that breathes in and out
Among Reticulum's variable stars, R Reticuli stands out as a Mira variable — a class of pulsating red giant that swells and contracts over months, causing its brightness to rise and fall dramatically. The reddish color of R Reticuli is a direct sign of its cool surface temperature, a hallmark of the evolved giant stars that populate this class. What makes the discovery story particularly interesting is its location in astronomical history: R Reticuli was found by C. Ragoonatha Chary at the Madras Observatory in India, adding it to the list of significant variable-star discoveries made outside the major European observatories that dominated nineteenth-century astronomy. Mira variables are important distance indicators and tracers of stellar aging, so even a faint southern-sky example like this one carries scientific weight beyond its modest appearance in a small telescope.
06 Epsilon Reticuli: a planet around an aging pair Deeper
The binary system Epsilon Reticuli sits about 50 light-years from the Sun, close enough that parallax measurements give a reliable distance. The primary star, Epsilon Reticuli A, is classified as spectral type K2IV — a subgiant, meaning it has already begun to evolve away from its main-sequence life, growing slightly larger and cooler than a star like the Sun. Its companion is a white dwarf, the dense stellar remnant left behind after a more massive star exhausted its fuel and shed its outer layers. That white dwarf is a ghost of a star that was once the more luminous of the two. In 2000, astronomers announced that a planetary companion orbits Epsilon Reticuli A, making this system one of the earlier confirmed cases of a planet found around a subgiant star. The system's architecture — a planet, an evolving host star, and a white-dwarf remnant nearby — offers a compressed snapshot of stellar and planetary evolution playing out in the same neighborhood.
07 Zeta Reticuli and a famous UFO claim
Zeta Reticuli is a wide binary star system roughly 39 light-years away, with both stars being physically similar to the Sun in mass and spectral type — making them, at least in principle, candidates to host habitable planets. The system's astronomical interest is genuine, but it became far more culturally famous after alleged alien abductees Betty and Barney Hill named Zeta Reticuli as the origin point of their abductors. The Hills described a star map they claimed to have seen aboard a spacecraft, and amateur investigators later argued it matched the Zeta Reticuli system. Astronomers have not found evidence supporting the alien-contact narrative, but the publicity cemented Zeta Reticuli as shorthand for extraterrestrial mystery in popular culture. From a purely stellar standpoint, however, it remains a well-studied pair of Sun-like stars offering a useful comparison point for understanding how stars similar to our own age and behave.
08 NGC 1559 and a stellar explosion caught in 2005 Deeper
Reticulum hosts the spiral galaxy NGC 1559, which gained scientific attention in 2005 when astronomers discovered a Type Ia supernova erupting within it. Type Ia supernovae are exceptionally important in cosmology: because they arise from a well-understood physical mechanism — a white dwarf accreting mass until it reaches a critical threshold and detonates — they produce a remarkably consistent peak brightness. That consistency makes them reliable cosmic distance markers, sometimes called standard candles, and observations of Type Ia supernovae in distant galaxies were central to the 1998 discovery that the universe's expansion is accelerating. Finding one in NGC 1559, a galaxy sitting within the boundaries of Reticulum, brought a moment of front-line cosmological research into this otherwise quiet constellation. The event also provides a vivid illustration of how any ordinary-looking galaxy in a modest southern constellation can suddenly flare into scientific relevance.
09 Reticulum II and the forge of heavy elements Deeper
The dwarf galaxy Reticulum II is one of the most scientifically discussed objects bearing this constellation's name. It is notably enriched in elements produced by the r-process — short for rapid neutron-capture process — which is one of the two main pathways by which the universe builds elements heavier than iron. The r-process requires an extreme environment with a flood of free neutrons, and the leading candidate sites are neutron-star mergers. Finding a dwarf galaxy with an unusual abundance of r-process elements gives astronomers a natural laboratory: because small, ancient galaxies like Reticulum II have had relatively simple star-formation histories, the heavy-element enrichment there is easier to trace back to specific events than it would be in a large, complex galaxy like the Milky Way. Reticulum II therefore sits at the intersection of nuclear astrophysics, galaxy evolution, and the question of where the gold and uranium in the universe actually came from.
10 A supercluster stretching a billion light-years away
Even by cosmic standards, the Horologium-Reticulum Supercluster is a structure of staggering scale. It spans a distance range from 700 million to 1.2 billion light-years from Earth — meaning that light from its far edge set out before complex animal life existed on this planet. A supercluster is a gravitationally related collection of galaxy clusters and groups, and this one takes its name from two of the southern constellations across whose projected directions it sprawls: Horologium and Reticulum. Structures of this kind represent some of the largest coherent features in the observable universe, and mapping them helps astronomers understand how matter clumped together over cosmic time under the competing influences of gravity and the universe's accelerating expansion. That a small, faint constellation like Reticulum lends its name to something this enormous is a reminder that the backgrounds of even the most modest star patterns reach unimaginably far into the universe.
11 Seasonal visibility and where you need to be
Reticulum rewards observers in the southern hemisphere, with the constellation best placed in the evening sky between October and December. Its southerly declination means that for anyone north of the 30th parallel north — roughly the latitude of New Orleans, Cairo, or Shanghai — the constellation either never rises above the horizon or skims so low that atmospheric haze makes it effectively invisible. Even Alpha Reticuli, the one star that might be spotted under ideal conditions from near that northern boundary, offers only a marginal view. The constellation covers a modest area and contains no stars that would jump out in a light-polluted sky. Southern-hemisphere observers, and those who travel to low-latitude dark sites, will find October through December evenings the optimal window, when Reticulum climbs to a comfortable altitude and its faint stellar field is accessible in binoculars against a properly dark sky.