Circinus, the Drafting Compass, is a small, faint southern constellation squeezed in beside Alpha Centauri, at the edge of the Milky Way.
At a glance
| stars in the figure | 3 |
|---|---|
| nearest star of the figure | Alpha Circini, 54 light-years (16.6 pc) |
| farthest star of the figure | Gamma Circini, 449 light-years (138 pc) |
| depth | the farthest is 8.3 × farther than the nearest |
Read off the piece’s own catalogue, the same values it draws with.
About Circinus
Circinus is one of the constellations introduced by Nicolas-Louis de Lacaille from the Cape of Good Hope. He named it after the pair of compasses used by surveyors and draughtsmen, and set it next to Norma, the set square, among a group of instruments in the southern Milky Way. It has no myth, and its stars carry no traditional names.
The figure is a narrow triangle of three stars, led by Alpha Circini, a white star close to the Sun. It is easiest to find by starting from Alpha Centauri, which lies right beside it. Behind its Milky Way star fields lies the Circinus Galaxy, an active galaxy so hidden by the dust of our own that it went unnoticed until the age of radio and infrared surveys.
What you see in the piece
From Earth the compass is a tight, neat wedge. Fly out with CONSTELLATIONS on and it opens out completely: Alpha Circini sits nearby while Gamma Circini lies far behind, and the points of the compass end up in different parts of the Sun’s surroundings.
Questions
How do you find Circinus?
Start from Alpha Centauri, the bright star at the foot of the Centaur: Circinus lies immediately next to it, between Alpha Centauri and Triangulum Australe. It is a southern constellation, best seen in the southern autumn and winter.
How far away are the stars of Circinus?
The nearest star of the figure is Alpha Circini, 54 light-years (16.6 pc) away, and the farthest is Gamma Circini, 449 light-years (138 pc), 8.3 × farther.