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Circinus

Constellation in the southern celestial hemisphere

Astronomical objectconstellationQ10508

Also known as Cir · Circini · the Compass

Overview

From Wikipedia, the free encyclopedia · Read full article · Text CC BY-SA 4.0

Circinus is a small, faint constellation in the southern sky, first defined in 1756 by the French astronomer Nicolas-Louis de Lacaille. Its name is Latin for compass, referring to the drafting tool used for drawing circles. Its brightest star is Alpha Circini, with an apparent magnitude of 3.19. Slightly variable, it is the brightest rapidly oscillating Ap star in the night sky. AX Circini is a Cepheid variable visible with the unaided eye, and BX Circini is a faint star thought to have been formed from the merger of two white dwarfs. Two sun-like stars have planetary systems: HD 134060 has two small planets, and HD 129445 has a Jupiter-like planet. Supernova SN 185 appeared in Circinus in 185 AD and was recorded by Chinese observers. Two novae have been observed more recently, in the 20th century.

Overview

All data

33 statements · 18% with external sources · numbers in brackets are citations

Discovered: 1756
Discovered by: Nicolas Louis de Lacaille
Short name: Cir
Named after: compass
Part of: Southern Celestial Hemisphere
Area: 93 square degree
Shares border with: Centaurus
Musca
Apus
Triangulum Australe
Norma
Lupus
Official name: Circinus
1
Sources
1.iau.org/public/themes/constellations/#n4
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On other databases

19 identifiers linking Circinus across the web's reference databases

Data quality

statements

18%

externally sourced

Source last edited August 13, 2026. AIDB refreshes this page daily.

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AIDB. (2026). Circinus (Q10508). Retrieved from https://aidb.si/e/circinus-Q10508