Constellations: Piscis Austrinus 'the Southern Fish'
Created | Updated Nov 8, 2017
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
Superb unreturning tide,
those silent waters weave for him
a fluctuant mutable world and dim...
- Rupert Brooke
|Name:||Piscis Austrinus (Latin: 'Southern Fish')|
|Area:||245 sq deg|
|Co-ordinates1:||Right Ascension 23h, Declination −39°|
On a bright moonlit night (or in an place containing street lights) this area of the sky, lying some 30 degrees south of the celestial equator, may look empty except for Fomalhaut which appears as a lone beacon in the autumn skies. Those in northern latitudes may find Piscis Austrinus2 is a bit too far south to observe; however more southerly viewers, under dark sky conditions with a pair of binoculars, will see plenty of stars.
The ancient observers connected these faint stars in their minds to make a fish lying on its back with its mouth open. Located below Aquarius, next to Microscopium and north of Grus, this constellation lies south of the Zodiac and should not be confused with Pisces. Some early star charts showed the water from Aquarius pouring into the open mouth. Stars of the adjacent constellation Grus, the Crane, were part of Piscis Austrinus until Astronomer Johann Bayer created Grus in the 17th Century. Several of Grus' stars carry Arabic names that reflect their previous inclusion in Piscis Austrinus.
This fish was once thought to have been connected to the Assyrian fish god Dagon, and before that to the figure Oannes. Oannes, they said, taught all manner of knowledge during the day, but at night turned into a fish and slept in the sea.
In one Greek myth two fish swam up and rescued Aphrodite and Eros when they were besieged by a monster on the river bank. Eratosthenes postulated that these were the offspring of what he labelled 'The Great Southern Fish'. These two fish became the Zodiacal constellation Pisces.
Beta is a line-of-sight double. The two stars of +4.3 and +7.9 magnitude are not physically connected.
A small grouping of fifth and sixth magnitude stars - five in all - including tau, mu, upsilon and nu Piscis Austrini, form a small bright asterism near the tail of the fish.
Eta, theta, iota and mu Piscis Austrini were known in Chinese astrology as Tien Tsien, 'Heavenly Cash'.
Alpha Piscis Austrini, Fomalhaut, is the brightest and only first magnitude star. This was one of four 'Royal Stars' in Mesopotamia. The Romans also observed this star from some of their southern provinces and called it Piscis Meridiani. The word Fomalhaut is derived from 'Fom al Hat' which translates as 'the mouth of the fish'. It has a ring some 15 AU (Astronomical Units) in diameter which is irregular in shape. Like the braided ring of Saturn, it was speculated that some unseen shepherd planets were determining the shape of this ring. In November 2008 Astronomy Picture of the Day featured Fomalhaut's dust disc, confirming a gas giant planet at 115 AU distance from the star.
This seventh magnitude red dwarf, located near pi Piscis Austrini, is in the list of ten closest stars. It was originally hoped that a planetary system would be found here but repeated attempts to find one proved to be unsuccessful.
|ε PsA||Epsilon||HD 214748||+4.17||744||B8|
|δ PsA||Delta||HD 216763||+4.21||160||G8|
|β PsA||Beta||HD 213398||+4.29||170||A0|
|ι PsA||Iota||HD 206742||+4.34||45||A0|
|γ PsA||Gamma||HD 206742||+4.46||222||A0|
|μ PsA||Mu||HD 210049||+4.5||130||A2|
|τ PsA||Tau||HD 210302||+4.92||62||F6|
|υ PsA||Upsilon||HD 210066||+4.99||360||F0|
|θ PsA||Theta||HD 207155||5.02||540||A1|
|π PsA||Pi||HD 217792||+5.11||63||A6|
|η PsA||Eta||HD 209014||+5.42||1,012||B8|
TABLE: NGC or IC
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.||Class||Brightness (m)||Distance
Three planetary systems had been found in this constellation by 2008. The size of these extrasolar planets is comparable to the mass of Jupiter, our Solar System's largest planet, known by astronomers as the 'Jovian scale'. Some exoplanets have been given proper names by the IAU. Fomalhaut b has been anointed Dagon, after the fish god of fertility and agriculture in Phoenician mythology.
|Fomalhaut||Fomalhaut b/Dagon||Approx 872 yrs||0.5||115 AU||2008|
|HD 216770||HD 216770 b||118.45 days||0.647||0.46 AU||2003|
|HD 205739||HD 205739 b||279.8 days||1.37||0.896 AU||2008|
|HD 207832||HD 207832 b||162 days||0.56||0.57 AU||2012|
|HD 207832||HD 207832 c||1,155 days||0.73||2.1 AU||2012|
|WASP-112||WASP-112 b||3.04 days||0.88||0.04 AU||2014|
|WASP-124||WASP-124 b||3.37 days||0.6||0.05 AU||2016|
The streak of light of the shooting star is caused by small specks of dust which burn up from friction with the air in the upper reaches of the Earth's atmosphere. The dust is usually from the trails of comets that have crossed the Earth's orbit leaving debris behind them. If the tracks of a number of meteors can be traced back to a common point of intersection, they are named from the star nearest to that point. This Constellation is host to seven minor meteor showers all of which occur in July and August. The most well known, Alpha Pisces Australids, was discovered in 1865 by Alexander S Herschel. Due to the orbital mechanics involved, if you live south of Earth's equator you will be more likely to observe these meteors. Here are the dates of these meteor showers.
|Alpha Pisces Australids||16 July-13 August|
|Theta Pisces Australids||12 August-14 August|
|Beta Pisces Australids||14 July-22 July|
|Lamba Pisces Australids||5 August-14 August|
|Epsilon Pisces Australids||13 August-14 August|
|Pi Pisces Australids||28 July-3 August|
|20 Pisces Australids||8 August-9 August|