Constellation, Unicorn
Monoceros
A unicorn prancing between the two dogs of Orion, introduced by Petrus Plancius in 1612. Its stars are faint, but it lies in the Milky Way and holds the Rosette Nebula.
From New York on October 13, 2026, the centre of Monoceros rises at 12:29 AM, is highest at 6:26 AM (48° above the horizon in the S) and sets at 12:28 PM.
In the 3D sky
The sky over New York turned towards Monoceros. 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 ancient Greeks knew no constellation here. The Dutch theologian and mapmaker Petrus Plancius filled the gap with a unicorn on a celestial globe of 1612, the same globe that first showed his giraffe, Camelopardalis. In 1624 the German astronomer Jacob Bartsch drew it on a star chart and was later wrongly credited with inventing it. Bartsch pointed to Bible passages that seemed to mention unicorns, although modern translations read ‘wild ox’ instead. The unicorn had long been a Christian symbol of purity. Being a modern figure, Monoceros has no myth.
Plancius had already drawn a unicorn on a world map of 1594, dipping its horn into a stream. That pose recalls the famous Hunt of the Unicorn tapestries woven about a century before. Johannes Hevelius adopted Monoceros in his atlas of 1690, which helped other astronomers accept it. None of its stars has a traditional name. Its best-known sight is the Rosette Nebula, a wreath of glowing gas with young stars inside.
Sources: Ian Ridpath, Star Tales: Monoceros
Brightest stars
| Star | Designation | Magnitude | Distance |
|---|---|---|---|
| β Mon | β Mon | 3.76 | 677 light-years |
| α Mon | α Mon | 3.94 | 148 light-years |
| γ Mon | γ Mon | 3.99 | 498 light-years |
| δ Mon | δ Mon | 4.15 | 384 light-years |
| ζ Mon | ζ Mon | 4.36 | 1,059 light-years |
| ε Mon | ε Mon | 4.39 | 122 light-years |
| 13 Mon | 13 Mon | 4.47 | unknown |
| 18 Mon | 18 Mon | 4.48 | 368 light-years |
| 15 Mon | 15 Mon | 4.66 | 919 light-years |
| 28 Mon | 28 Mon | 4.69 | 450 light-years |
Facts
| Area | about 481 square degrees (35 of 88) |
|---|---|
| IAU abbreviation | Mon |
| Sky | Near the celestial equator, visible from both hemispheres |
| Origin | First shown as Monoceros Unicornis on a celestial globe by Plancius in 1612 |
| Stars brighter than magnitude 5 | 15 |
| Centre (J2000) | 7.0 h, -1° |
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 |
|---|---|---|
| NGC2232 | Open cluster | 3.9 |
| NGC2264 · Christmas Tree Cluster | Cluster with nebula | 3.9 |
| NGC2239 | Cluster with nebula | 4.8 |
| M50 | Open cluster | 5.9 |
| NGC2238 · Rosette Nebula | HII region | 6.0 |
| NGC2301 · Great Bird Cluster | Open cluster | 6.0 |
| NGC2343 | Open cluster | 6.7 |
| NGC2353 | Open cluster | 7.1 |
| NGC2335 | Open cluster | 7.2 |
| NGC2251 | Open cluster | 7.3 |
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.