|Pronunciation||or , genitive|
|Symbolism||the Southern Fish|
|Area||245 sq. deg. (60th)|
|Stars with planets||3|
|Stars brighter than 3.00m||1|
|Stars within 10.00 pc (32.62 ly)||3|
|Brightest star||Fomalhaut (α PsA) (1.16m)|
(10.74 ly, 3.29 pc)
Visible at latitudes between +55° and −90°.
Best visible at 21:00 (9 p.m.) during the month of October.
Piscis Austrinus (also known as Piscis Australis) is a constellation in the southern celestial hemisphere. The name is Latin for "the southern fish", in contrast with the larger constellation Pisces, which represents a pair of fishes. Prior to the 20th century, it was also known as Piscis Notius. Its only star brighter than 4th magnitude is Fomalhaut, which is a first-magnitude star and is the 18th brightest star in the night sky.
Piscis Austrinus was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations. The stars of the modern constellation Grus once formed the "tail" of Piscis Austrinus. In 1597 (or 1598), Petrus Plancius carved out a separate constellation and named it after the crane.
In Greek mythology, this constellation is known as the Great Fish and it is portrayed as swallowing the water being poured out by Aquarius, the water-bearer constellation. The two fish of the constellation Pisces are said to be the offspring of the Great Fish. In Egyptian mythology, this fish saved the life of the Egyptian goddess Isis, so she placed this fish and its descendants into the heavens as constellations of stars.
Pisces Austrinus originated with the Babylonian constellation simply known as the Fish (MUL.KU).
Piscis Austrinus is a constellation bordered by Capricornus to the northwest, Microscopium to the southwest, Grus to the south, Sculptor to the east, Aquarius to the north. The recommended three-letter abbreviation for the constellation, as adopted by the International Astronomical Union in 1922, is 'PsA'. The official constellation boundaries, as set by Eugène Delporte in 1930, are defined by a polygon of four segments. In the equatorial coordinate system, the right ascension coordinates of these borders lie between 21h 27.3m and 23h 06.5m, while the declination coordinates are between -24.83° and -36.46°.
Fomalhaut traditionally represents the mouth of the fish. Its companion Fomalhaut b was thought to be the first extrasolar planet ever detected by a visible light image, thanks to the Hubble Space Telescope, but infrared observations have since retracted this claim: it is instead a spherical cloud of dust. TW Piscis Austrini can be seen close by and is possibly associated with Fomalhaut as it lies within a light year of it. Of magnitude 6.5, it is a BY Draconis variable.
Beta, Delta and Zeta constitute the Tien Kang ("heavenly rope") in China. Beta is a white star of apparent magnitude 4.29 and spectral type A0, and lies 130 light years away. Delta Piscis Austrini is a double star with components of magnitude 4.2 and 9.2.
S Piscis Austrini is a long period Mira-type variable red giant which ranges between magnitude 8.0 and 14.5 over a period of 271.7 days, and V Piscis Austrini is a semi-regular variable ranging between magnitudes 8.0 and 9.0 over 148 days.
- Condos, Theony; Eratosthenes; Hyginus (1997). Star myths of the Greeks and Romans: a sourcebook containing the Constellations of Pseudo-Eratosthenes and the Poetic astronomy of Hyginus. Red Wheel/Weiser. pp. 163–164.
- "Piscis Austrinus, constellation boundary". The Constellations (International Astronomical Union). Retrieved 20 August 2012.
- Moore, Patrick (2011). Patrick Moore's Data Book of Astronomy. Cambridge University Press. p. 472.
- Richard Hinckley Allen: Star Names — Their Lore and Meaning: Piscis Australis, the Southern Fish
- Kaler, Jim (12 November 2009). "Beta PsA".
- Ian Ridpath and Wil Tirion (2007). Stars and Planets Guide, Collins, London. ISBN 978-0-00-725120-9. Princeton University Press, Princeton. ISBN 978-0-691-13556-4.
- The Deep Photographic Guide to the Constellations: Piscis Austrinus
- Star Tales – Piscis Austrinus
- Piscis Austrinus at Constellation Guide