Constellations: Reticulum 'the Reticle' Content from the guide to life, the universe and everything

Constellations: Reticulum 'the Reticle'

2 Conversations

The shield of the Science, Mathematics and Engineering faculty of the h2g2 University.Constellations: Overview | Andromeda | Antlia | Apus | Aquarius | Aquila | Ara | Aries | Auriga | Boötes | Caelum
Camelopardalis | Cancer | Canes Venatici | Canis Major | Canis Minor | Capricornus | Carina | Cassiopeia | Centaurus
Cepheus | Cetus | Chamæleon | Circinus | Columba | Coma Berenices | Corona Australis | Corona Borealis | Corvus
Crater | Crux | Cygnus | Delphinus | Dorado | Draco | Equuleus | Eridanus | Fornax | Gemini | Grus | Hercules | Horologium
Hydra | Hydrus | Indus | Lacerta | Leo | Leo Minor | Lepus | Libra | Lupus | Lynx | Lyra | Mensa | Microscopium | Monoceros
Musca | Norma | Octans | Ophiuchus | Orion | Pavo | Pegasus | Perseus | Phoenix | Pictor | Pisces | Piscis Austrinus
Puppis | Pyxis | Reticulum | Sagitta | Sagittarius | Scorpius | Sculptor | Scutum | Serpens | Sextans | Taurus
Telescopium | Triangulum | Triangulum Australe | Tucana | Ursa Major | Ursa Minor | Vela | Virgo | Volans | Vulpecula

Name:Reticulum ('Reticle')
Short form:Ret
Area:114 sq deg
Co-ordinates1:04h, −60°

So what is a reticle? The name comes from the Latin for net, and it is an overlay bearing a grid of fine lines, used to mark or measure positions. Reticulum is best seen by observers in the Southern Hemisphere. It makes its highest appearance in November. The constellation is bordered by Horologium, Dorado and Hydrus.


Before Reticulum was first drawn, an earlier constellation by the astronomer Isaac Habrecht (1589 - 1633)2 stood in this position. Nicolas Louis de Lacaille (1713 - 1762) set up an observatory in South Africa where he worked from 1751 to 1753. At that observatory he used a rhomboidal reticle. He named this constellation 'le reticle romboide' in honour of this instrument. Reticulum does not have any myths because it is a modern constellation.


Johannes Bayer set up the current system of calling the brightest star 'alpha' and then proceeding down the Greek alphabet for subsequent stars. The combination of this letter with the genitive of the constellation name is known as the 'Bayer Designation'. Many dimmer stars such as HD 27894 have neither a name nor a Bayer Designation.

Gamma Reticuli varies slightly over the space of 25 days. Its magnitude varies between +4.42 and +4.61.

Star Table

StarDesignationName or
catalogue number
(light years)
Spectral classification
and/or comments
α RetalphaHR 1336+3.35250G8
β RetbetaHR 1175+3.8578K1
γ RetgammaHR 1264+4.513490M4
δ RetdeltaHR 1247+4.56530M2
ε RetepsilonHR 1355+4.4459K2
ζ1 Retzeta1HR 1006+5.5440G2
ζ2 Retzeta2HR 1010+5.2440G2
η Reteta HR 1395+5.24380G8
θ RetthetaHR 1372+5.87462B9
ι RetiotaHR 1266+4.9747K4
κ RetkappaHR 1083+4.7270F5
-unnamedHD 27894+9.20138K2

Deep Sky Objects

NGC 1313 is a barred spiral galaxy 15 megalight-years away. Observed at shorter wavelengths it is more ordered than in visible light, and exhibits signs of being rich in hydrogen which would make it a nursery for new stars.

The New General Catalogue by J Dreyer was published by the Royal Astronomical Society in the late 19th Century. It was expanded to include two Index Catalogues (IC). This list of star clusters, nebulae and galaxies was revised again in 1973 and is continually updated by the NGC/IC Project.

Cat. No.Type of ObjectBrightness (m)Distance
(Mega-light years)
NGC 1313galaxy+9.215
NGC 1536galaxy+12.754
NGC 1543galaxy+10.352
NGC 1574galaxy+10.747
IC 2037galaxy+14.7364
IC 2049galaxy+14.565
IC 2056 galaxy+12.550
IC 2060galaxy+15.17294

Extrasolar Planets

Here are some planetary systems that have been found in this constellation. The size of these extrasolar planets is compared to the mass of Jupiter. This is known by astronomers as the 'Jovian scale'.

The star HD 27894 has a proper motion about 26% of that of Barnard's Star. There have been claims that it has planets at 0.07, 0.12, and 0.41 Astronomical Units, but only the one at 0.12 AU (HD 27894 b) has been confirmed.

Star name or
catalogue number
catalogue number
Planet mass
(Jovian scale)
Orbital period
(Earth days)
epsilon ReticuliHD 27442 b1.281.18423.8
HD 23079HD 23079 b2.611.16738.45
HD 23127HD 23127 b1.52.41,214
HD 27894HD 27894 b0.620.1218
HD 25171HD 25171 b0.9531,845
zeta2 ReticuliHD 20807 b40.270.1418.9
WASP-100WASP-100 b2.030.04572.85
WASP-119WASP-119 b1.230.0362.5
HD 21693HD 21693 b0.030.1522.66
HD 21693HD 21693 c0.060.2653.88


It may be a hoax, a delusion, or a hidden truth; but there are those who believe that we have been visited by beings from zeta2 Reticuli. In 1961 two people in New Hampshire saw an object in the sky. They claim they stopped the car and the husband trained a pair of binoculars on the object. The next thing they knew (according to their testimony) it was two hours later. Under hypnosis the story emerged that they were taken aboard a UFO and the woman was shown a map. The stars on the map were not labelled. The map she said she saw was three dimensional. The one she drew under hypnotic regression was not. The Boston psychiatrist5 who examined her and her husband concluded that the story was not a deliberate fabrication. It was several years before any star names were added to this map. A tentative map was drawn up by an amateur astronomer in Ohio, connecting it to the star zeta2 Reticuli, and then a professor at OSU6 had his students enter star locations in a computer and generated a map. Finally Mark Steggert of the University of Pittsburgh used a program he had written and the maps were compared. This whole incident was written up in the December 1974 issue of Astronomy magazine.

Four decades later, following the death of her husband, the woman still believes that she was taken aboard a UFO by extra-terrestrials and that the star system from which her abductors came was that of zeta2 Reticuli. In 1995 a group of extrasolar planets was listed in the Extrasolar Planet Encyclopedia including zeta2 Reticuli. However, when the link to ufology was realised, the listing was rejected. The reason given was that 'the data may have been misinterpreted'.

1Current IAU guidelines use a plus sign (+) for northern constellations and a minus sign (−) for southern ones.2Grandson of clockmaker Isaac Habrecht (1544 - 1620).3Slightly variable.4After being published for four days authorities disavowed the existence of this planet.5Benjamin Simon.6Ohio State University.

Bookmark on your Personal Space

Edited Entry


Infinite Improbability Drive

Infinite Improbability Drive

Read a random Edited Entry

Categorised In:

Written by

Edited by

h2g2 Editors


h2g2 Entries

External Links

Not Panicking Ltd is not responsible for the content of external internet sites

Write an Entry

"The Hitchhiker's Guide to the Galaxy is a wholly remarkable book. It has been compiled and recompiled many times and under many different editorships. It contains contributions from countless numbers of travellers and researchers."

Write an entry
Read more