Genitive: Coronae Australis

Abbreviation: CrA

Size ranking: 80th

Origin: One of the 48 Greek constellations listed by Ptolemy in the Almagest

Greek name: Στέφανος Nότιος (Stephanos Notios)

 

Corona Australis was known to the Greeks not as a crown but as a wreath, which is how it is depicted on old star maps. Aratus did not name it as a separate constellation but referred to it simply as a circlet of stars beneath the forefeet of Sagittarius. Hyginus said it was a wreath cast off by the archer ‘as by one at play’.

 

Its first recorded mention as a separate constellation appears to be in the first century BC by the Greek astronomer and mathematician Geminus of Rhodes in his survey of astronomy called Introduction to the Phenomena. He gave it the name Νότιος στέφανος (Notios stephanos, the southern crown), whereas Ptolemy in the Almagest two centuries later reversed the name as Στέφανος νότιος (Stephanos notios). The northern crown, which we call Corona Borealis, was known to the Greeks simply as Στέφανος (Stephanos). Geminus said that the arc of stars was also known as a canopy (Οὐρανίσκος), as found over a throne, although he did not explain whose throne it might be.

 

Ptolemy listed 13 component stars in the southern crown, although one of them has since been reassigned to the adjoining modern figure Telescopium, where it is known as Alpha Telescopii. Bayer allocated Greek letters to Ptolemy’s 13 stars on his Uranometria atlas of 1603, but Lacaille relabelled the constellation in his Coelum Australe Stelliferum of 1763 and it is Lacaille’s letters that are still used today.