Circinus (Pronounciation:Sir-sin-us, Abbrev:Cir, Latin:Circini) is a constellation, one of 88 constellations that the night sky is divided into. The sky is not divided up equally between the constellations. Circinus takes up 93.353 sq. degrees of the night sky which equates to 0.23% of the night sky. Circinus is the 85th largest in terms of size in the night sky.
The constellation name means The Compasses . It was not one of the original constellations that had been devised by Ptolemy, instead it was created by Abbé Nicolas Louis de Lacaille years later.
There are 4 stars that make up the main constellation. The hipparcos satellite scanned and detailed 457 stars. There are 21 stars that can be seen with the naked eye in the constellation on a very clear night sky.
Circinus is not a member of the Zodiac group of twelve constellations that appear when the Sun sets. Circinus is a southern hemispheric constellation which means it can't be seen easily or at all from the northern hemisphere.
The distance to Circinus is not calculable because all the stars that make up the constellation are at various distances. The best answer for distance to Circinus is to calculate the average distance of the stars.
There are 4 Extrasolar Planets (Exoplanets) in this constellation that are detailed on this site. There is a dedicated page for exoplanets in Circinus.
There are no deep space objects that were identified by Charles Messier in this constellation. There are no non-Messier deep space objects in this constellation that are covered at present on this site.
The image at the top right of this page was generated using Night Vision, a free to use and download application by Brian Simspon.
The caveat of these stars are that they are catalogued on this site. If you know of a star that is nearer or further then do let me know in the comments and I'll add it to the site. The stars mentioned are from the Hipparcos catalogue or have been added because of their special status.
The nearest star to Earth is Alpha Circini which is roughly about 54.05 Light Years from the Earth. The nearest star to the Earth with an exoplanet is HD 134060 which is about 78.94 Light Years.
The furthest star that is located in the constellation is HIP 72967 and it is 326163.3 light years away from the Sun. The furthest figure is derived from either the 1997 or 2007 Hipparcos star catalogue parallax figure and it has been known to produce distances that are wrong.
The brightest star in Circinus is Alpha Circini and is located about 196.84 light years from the Sun. The star has a apparent magnitude of 3.18 but an absolute magnitude of 2.08 when the star is viewed from a distance of 10 Parsecs or 32.6 Light Years. The star is recognised as being the brightest in the constellation as it has the Bayer status of Alpha.
The dimmest star that can be seen in Circinus with the naked eye is HD 121932. The dim star has an apparent magnitude of 5.96. The dimmest star that a person is able to see with their naked eye is 6.0 magnitude based on the table in the reference. Ref: University of Michigan.
It is a southern constellation and would not have problem been seen by the Greeks at the time. There is no Greek Legend behind this constellation. It was created by Abbé Nicolas Louis de Lacaille to fill in the voids in the astronomical charts.
| Name | Circinus |
| Abbreviation | Cir |
| Is a Zodiac Sign | No |
| Brightest Star | Alpha Circini |
| Area | 93.353 sq. deg. |
| Percentage of Night Sky | 0.23% |
| Size Position | 85th |
| Hemisphere | Southern |
| Site Exoplanet Count | 4 |
| Meteor Shower Count | 1 |
| Nearest Star | Alpha Circini |
| Nearest Star with Exoplanet(s) | HD 134060 |
| Brightest Star | Alpha Circini |
| Dimmest Star | HD 121932 |
| Furthest Star | HIP 72967 |
| Bright Star Count | 21 |
| Hipparcos Star Count | 457 |
| Main Star Count | 4 |
| Messier Deep Space Object Count | 0 |
| *Non-Messier Deep Space Object Count | 0 |
| Bordering / Neighbouring / Surrounding Constellations | Lupus |
| Centaurus | |
| Musca | |
| Apus | |
| Triangulum Australe | |
| Norma | |
*Note: The number of Non-Messier Deep Space Object Count relates to how many are covered on this site not how many there are.