Circinus or the Compass is a small, inconspicuous constellation in the southern hemisphere, first listed in the 18th century by the French astronomer Nicolas Louis de Lacaille, who wanted to fill the gap between Centaurus'
forefeet and the constellation Triangulum Australe
. Circinus represents a pair of dividing compasses used by navigators for measuring distances.
The constellation Circinus occupies an area of 93 square degrees and does not contain any stars with known planets. It can be seen at latitudes between +10° and -90° and is best visible at 9 p.m. during the month of June.
The brightest star in Circinus is 
alpha Circini, a variable star with a magnitude of 3.18. It is a visual double with a faint companion star. The second brightest star, 
beta Circini, is an A-type main sequence star with a magnitude of 4.1. 
gamma Circini is a binary star that consists of a very close pair of contrasting blue and yellow stars.
Circinus has two notable deep sky objects. Circinus X-1 is an X-ray binary star that consists of a neutron star that orbits around a regular main sequence star. It lies approximately 20,000 light-years away from Earth.
The Circinus Galaxy is a spiral active galaxy 15 million light-years distant, discovered in 1975. It is interesting for the tumultuous gas motions occurring in it, most of them forming two discernible rings. One of the rings seems to be undergoing massive star formation. The inner ring is believed to be surrounding a massive black hole.
Circinus belongs to the Lacaille family of constellations, along with Norma
Constellations directly bordering Circinus are Centaurus
, Triangulum Australe