Constellation, Carpenter's Square
Norma
A set square and ruler, tools of the architect, placed among faint southern stars by Nicolas Louis de Lacaille. It belongs to a small group of drawing and surveying instruments.
From New York the constellation Norma never rises above the horizon: it belongs to the other hemisphere’s sky.
From New York the constellation Norma never rises above the horizon: it belongs to the other hemisphere’s sky.
In the 3D sky
The sky over New York turned towards Norma. Drag to look around.
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Evening visibility over the year
Height of the constellation’s centre above the horizon at 10 pm local time on the 15th of each month, from New York. Above about 30° it is well placed.
Name and history
The French astronomer Nicolas Louis de Lacaille mapped the southern sky from the Cape of Good Hope in 1751–52. He made this figure from faint stars between Ara and Lupus that Ptolemy had not listed. On his chart of 1756 he called it l’Equerre et la Regle, and in his notes he described it as an architect’s set square and ruler. He placed it next to his compasses, now Circinus, and drew the older Triangulum Australe as a surveyor’s level. Together they form a trio of drawing and surveying tools. Lacaille shortened the name to the Latin Norma in 1763.
There is no myth here. The figure has lost its stars labelled Alpha and Beta because later boundary changes moved them into Scorpius. The historian R. H. Allen called Norma ‘the Level and Square’ after misreading a French atlas. In fact the name ‘level’ belonged to Triangulum Australe, and his error has caused confusion ever since. Chinese astronomers counted some of its stars in a battalion of soldiers centred on Scorpius.
Sources: Ian Ridpath, Star Tales: Norma
Brightest stars
| Star | Designation | Magnitude | Distance |
|---|---|---|---|
| γ2 Nor | γ2 Nor | 4.01 | 129 light-years |
| ε Nor | ε Nor | 4.46 | 530 light-years |
| ι1 Nor | ι1 Nor | 4.63 | 129 light-years |
| η Nor | η Nor | 4.65 | 220 light-years |
| δ Nor | δ Nor | 4.73 | 122 light-years |
| μ Nor | μ Nor | 4.86 | unknown |
| κ Nor | κ Nor | 4.95 | 428 light-years |
| γ1 Nor | γ1 Nor | 4.97 | 1,469 light-years |
Facts
| Area | about 164 square degrees (74 of 88) |
|---|---|
| IAU abbreviation | Nor |
| Sky | Southern sky |
| Origin | First shown as l’Equerre et la Regle on Lacaille’s planisphere of 1756, from his observations at the Cape in 1751–52 |
| Stars brighter than magnitude 5 | 8 |
| Centre (J2000) | 16.3 h, -50° |
Deep-sky objects
Galaxies, clusters and nebulae brighter than magnitude 9, from the OpenNGC catalogue. Most need binoculars or a telescope and a dark sky.
| Object | Type | Magnitude |
|---|---|---|
| NGC6087 · S Nor Cluster | Open cluster | 5.4 |
| NGC6067 | Open cluster | 5.6 |
| NGC6169 | Open cluster | 6.6 |
| NGC6167 | Open cluster | 6.7 |
| NGC6164 | Nebula | 6.7 |
| NGC6165 | Nebula | 6.7 |
| NGC6134 | Open cluster | 7.2 |
| NGC6152 | Open cluster | 8.1 |
| NGC5925 | Open cluster | 8.4 |
| NGC6031 | Open cluster | 8.5 |
Boundaries: International Astronomical Union, via Astronomy Engine. Areas are computed from the boundaries by sampling (within about one percent). Names and lines: Stellarium. Stars: HYG Database. Deep-sky objects: OpenNGC. Calculated with Astronomy Engine, an open-source library verified against the US Naval Observatory and NASA JPL. Data sources
How to use this page
Choose your place and a night at the top. The answer and the 3D view show where the constellation is, when it is highest and whether it rises at all from where you are. The chart shows its stars and lines, and the tables list its brightest stars and the deep-sky objects inside it.
Frequently asked questions
When is a constellation best seen?
When it is highest in a dark sky, which the page gives for the night you pick. Each constellation is best placed in a particular season, because the stars rise about four minutes earlier every night.
Why can I not see a constellation from my place?
Constellations far south of the celestial equator never rise from northern places, and those far north never rise from southern ones. The page says when this is the case.
What are the constellation boundaries?
The International Astronomical Union divides the sky into 88 areas with official boundaries. The stick figures are only a drawing aid, the boundaries say which constellation a point in the sky belongs to.
Related guides
- How to learn the constellationsStart with one bright pattern you cannot miss, use it as a signpost to its neighbours, and come back a month later: the sky will have turned, and you will know a little more of it.
- Altitude and azimuth: finding things in the skyTwo angles tell you exactly where to look: which direction, and how high.
- Light pollution and dark skies: the Bortle scaleFrom a city centre you can count a few dozen stars. From a truly dark site you can count a few thousand, with the Milky Way bright enough to cast a shadow. The Bortle scale puts a number on the difference.
- Binoculars for stargazing: what to buy and what to look atA pair of 7x50 or 10x50 binoculars shows the craters of the Moon, the moons of Jupiter, dozens of star clusters and the Andromeda Galaxy, for a fraction of the cost of a telescope.