Reticulum is a small, faint

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

in the

southern sky The southern celestial hemisphere, also called the Southern Sky, is the southern half of the celestial sphere; that is, it lies south of the celestial equator. This arbitrary sphere, on which seemingly fixed stars form constellations, appears ...

. Its name is

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

for a small

net Net or net may refer to: Mathematics and physics * Net (mathematics), a filter-like topological generalization of a sequence * Net, a linear system of divisors of dimension 2 * Net (polyhedron), an arrangement of polygons that can be folded up ...

, or

reticle A reticle, or reticule also known as a graticule, is a pattern of fine lines or markings built into the eyepiece of an optical device such as a telescopic sight, spotting scope, theodolite, optical microscope or the screen of an oscilloscope, ...

—a net of crosshairs at the focus of a telescope eyepiece that is used to measure star positions. The constellation is best viewed between October and December, and save for one main star visible in ideal conditions, cannot be seen from north of the 30th parallel north.

History

A constellation in this area was introduced by

Isaac Habrecht II Isaac Habrecht II (1589–1633) was a professor of astronomy and mathematics in Strasbourg. He was also a doctor of medicine and philosophy. Uranography Isaac Habrecht II made a celestial globe and a couple of celestial planispheres.Habrecht II, ...

in his

celestial globe Celestial globes show the apparent positions of the stars in the sky. They omit the Sun, Moon, and planets because the positions of these bodies vary relative to those of the stars, but the ecliptic, along which the Sun moves, is indicated. The ...

in 1621, who named it ''Rhombus''. It was replaced with a somewhat different constellation by the French astronomer

Nicolas Louis de Lacaille Abbé Nicolas-Louis de Lacaille (; 15 March 171321 March 1762), formerly sometimes spelled de la Caille, was a French astronomer and geodesist who named 14 out of the 88 constellations. From 1750 to 1754, he studied the sky at the Cape of Good ...

in the eighteenth century; during his stay at the

Cape of Good Hope The Cape of Good Hope ( af, Kaap die Goeie Hoop ) ;''Kaap'' in isolation: pt, Cabo da Boa Esperança is a rocky headland on the Atlantic coast of the Cape Peninsula in South Africa. A common misconception is that the Cape of Good Hope is t ...

, he named the constellation le Réticule Rhomboide to commemorate the reticle in his telescope eyepiece. The name was later Latinized to Reticulum in his star catalogue ''Coelum Australe Stelliferum''. In 1810, the stars of Reticulum were used by William Croswell to produce the constellation '' Marmor Sculptile'', which represented the bust of

Christopher Columbus Christopher Columbus * lij, Cristoffa C(or)ombo * es, link=no, Cristóbal Colón * pt, Cristóvão Colombo * ca, Cristòfor (or ) * la, Christophorus Columbus. (; born between 25 August and 31 October 1451, died 20 May 1506) was a ...

, but this did not catch on among astronomers. The constellation Reticulum became officially recognized during the First General Assembly of the

International Astronomical Union The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...

in 1922. The boundary for this and other constellations was drawn up by Belgian astronomer

Eugène Delporte Eugene is a common male given name that comes from the Greek εὐγενής (''eugenēs''), "noble", literally "well-born", from εὖ (''eu''), "well" and γένος (''genos''), "race, stock, kin".right ascension Right ascension (abbreviated RA; symbol ) is the angular distance of a particular point measured eastward along the celestial equator from the Sun at the March equinox to the (hour circle of the) point in question above the earth. When paired w ...

and

declination In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. Declination's angle is measured north or south of the ...

for epoch 1875. These were published in 1930 in the ''Delimination Scientifique des Constellations'' at the behest of the IAU.

Features

Only two of the stars in this constellation are brighter than

visual magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's ...

Alpha Alpha (uppercase , lowercase ; grc, ἄλφα, ''álpha'', or ell, άλφα, álfa) is the first letter of the Greek alphabet. In the system of Greek numerals, it has a value of one. Alpha is derived from the Phoenician letter aleph , whic ...

(α) and

Beta Beta (, ; uppercase , lowercase , or cursive ; grc, βῆτα, bē̂ta or ell, βήτα, víta) is the second letter of the Greek alphabet. In the system of Greek numerals, it has a value of 2. In Modern Greek, it represents the voiced labiod ...

(β) reticuli. The reddish star

R Reticuli R Reticuli is a Mira variable star in the southern constellation Reticulum. It is an aging red giant star on the asymptotic giant branch with a stellar classification that varies between M4e to M7.5e, being hottest near maximum visual mag ...

is a

Mira variable Mira variables (named for the prototype star Mira) are a class of pulsating stars characterized by very red colours, pulsation periods longer than 100 days, and amplitudes greater than one magnitude in infrared and 2.5 magnitude at visual wavelen ...

. This variable was discovered by C. Ragoonatha Chary at the

Madras Observatory The Madras Observatory was an astronomical observatory which had its origins in a private observatory set up by William Petrie in 1786 and later moved and managed by the British East India Company from 1792 in Madras (now known as Chennai). The ...

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

. The

binary star A binary star is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separate stars, in wh ...

system

Epsilon Reticuli Epsilon Reticuli, Latinized from ε Reticuli, is a double star approximately 59 light-years away in the constellation of Reticulum. The primary component is an orange subgiant, while the secondary is a white dwarf. The two sta ...

consists of a

spectral class In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the ...

K2IV star being orbited by a

white dwarf A white dwarf is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to the Sun's, while its volume is comparable to the Earth's. A white dwarf's faint luminosity comes fro ...

. Based on

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby objects ...

measurements, this system is located about 50

light year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s from the Sun. In 2000, a planetary companion was announced, orbiting the star ε Reticuli A.

Zeta Reticuli Zeta Reticuli, Latinized from ζ Reticuli, is a wide binary star system in the southern constellation of Reticulum. From the southern hemisphere the pair can be seen with the naked eye as a double star in very dark skies. Based ...

is a wide binary star system, with both members being similar to the Sun. It is located at a distance of about 39 light years. This system gained some notoriety in

ufology Ufology ( ) is the investigation of unidentified flying objects (UFOs) by people who believe that they may be of extraordinary origins (most frequently of extraterrestrial alien visitors). While there are instances of government, private, and f ...

when the alleged alien abductees

Betty and Barney Hill Barney and Betty Hill were an American couple who claimed they were abducted by extraterrestrials in a rural portion of the state of New Hampshire from September 19 to 20, 1961. The incident came to be called the "Hill Abduction" and the "Zeta R ...

named it as the home of their abductors. In 2005, a

type 1a supernova A Type Ia supernova (read: "type one-A") is a type of supernova that occurs in binary systems (two stars orbiting one another) in which one of the stars is a white dwarf. The other star can be anything from a giant star to an even smaller white ...

was discovered in the spiral galaxy

NGC 1559 NGC 1559 is a barred spiral galaxy in the constellation Reticulum. It is also a Seyfert galaxy. Although it was originally thought to be a member of the Dorado Group, subsequent observations have shown that it is in fact not a member of any gala ...

, located in the constellation. The dwarf galaxy

Reticulum II Reticulum II (or Reticulum 2) is a dwarf galaxy in the Local Group. Reticulum II was discovered in 2015 by analysing images from the Dark Energy Survey. It is a satellite of the Magellanic Clouds and was probably captured relatively recently. Like ...

is enriched in

r-process In nuclear astrophysics, the rapid neutron-capture process, also known as the ''r''-process, is a set of nuclear reactions that is responsible for the creation of approximately half of the atomic nuclei heavier than iron, the "heavy elements", ...

heavy elements. The

Horologium-Reticulum Supercluster The Horologium-Reticulum Supercluster, is a massive supercluster spanning around 550 million light-years. It has a mass of around 1017 solar masses, similar to that of the Laniakea Supercluster, which houses the Milky Way. It is centered on coord ...

is a galaxy

supercluster A supercluster is a large group of smaller galaxy clusters or galaxy groups; they are among the largest known structures in the universe. The Milky Way is part of the Local Group galaxy group (which contains more than 54 galaxies), which in turn ...

that ranges from 700 million to 1.2 billion light-years from Earth.

References

External links

The Deep Photographic Guide to the Constellations: Reticulum

{{DEFAULTSORT:Reticulum Southern constellations IAU constellations Constellations listed by Lacaille

History

Features

See also

References

External links