Hercules constellation
Hercules (the Hero Hercules) is a constellation in the northern sky, best seen in the evening in July. Its brightest star is Kornephoros (magnitude 2.77). It contains the Keystone. Hercules covers 1,225 square degrees and is the 5th-largest of the 88 constellations.
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Detailed star map of Hercules
Facts
| Latin name | Hercules (genitive: Herculis) |
|---|---|
| Abbreviation | Her |
| Meaning | the Hero Hercules |
| Area | 1,225 square degrees (5th of 88) |
| Location | right ascension 17.3 h, declination +28° |
| Visible from | latitudes 90° N to 39° S (whole constellation) |
| Best month | July (at about 9 pm) |
| Brightest star | Kornephoros |
| Stars brighter than magnitude 6 | 145 |
| Named stars (IAU) | 6 |
| Messier objects | M13, M92 |
| Neighbors | Aquila, Boötes, Corona Borealis, Draco, Lyra, Ophiuchus, Serpens, Sagitta, Vulpecula |
How to find Hercules
From 40° N (the USA, southern Europe, Japan) look south in July evenings: at about 9 pm Hercules stands highest, around 78° above the southern horizon. From 35° S (Australia, South Africa, Argentina) it is highest in the north, about 27° above the horizon. The months before and after (June and August) are also good: then it is up a couple of hours earlier or later.
Hercules borders Aquila, Boötes, Corona Borealis, Draco, Lyra, Ophiuchus, Serpens, Sagitta and Vulpecula.
Asterisms with stars in Hercules: Keystone.
Stars of Hercules
Hercules has 145 stars brighter than magnitude 6, the limit of the naked eye under a dark sky. These are the brightest:
| Star | Designation | Magnitude | Type | Distance |
|---|---|---|---|---|
| Kornephoros | β Herculis | 2.77 | G7IIIa | 230 ly |
| — | ζ Herculis | 2.81 | G0IV | — |
| Sarin | δ Herculis | 3.14 | A3IV | 77 ly |
| — | π Herculis | 3.16 | K3IIab | — |
| — | μ Herculis | 3.42 | G5IV | — |
| Rasalgethi | α1 Herculis | 3.48 | M5Ib-II | 360 ly |
| — | η Herculis | 3.53 | G7.5IIIbFe-1 | — |
| — | ξ Herculis | 3.7 | G8+III | — |
| — | γ Herculis | 3.75 | A9III | — |
| — | ι Herculis | 3.8 | B3IV | — |
| — | ο Herculis | 3.83 | B9.5V | — |
| — | 109 Herculis | 3.84 | K2.5IIIab | — |
Deep-sky objects in Hercules
Hercules contains 2 objects from Charles Messier's catalog:
- Hercules Globular Cluster (M13): globular cluster, 5.8 mag
- Messier 92 (M92): globular cluster, 6.5 mag
Printable Hercules map and outline
A black and white version for printing and a plain outline of the Hercules figure, useful for school projects, worksheets and learning to recognize the shape.
History
Hercules is one of the 48 constellations listed by Ptolemy in the Almagest (2nd century AD). Its official boundary was drawn by Eugène Delporte for the International Astronomical Union in 1930.
Questions about Hercules
What is the brightest star in Hercules?
Kornephoros, at magnitude 2.77, about 230 light-years away.
When can you see Hercules?
Hercules is best seen in the evening in July. The whole constellation is visible from latitudes between 90° N and 39° S.
How many stars are in Hercules?
145 stars in Hercules are brighter than magnitude 6 and can be seen with the naked eye under a dark sky; 6 of them have official IAU names.
What does Hercules mean?
Hercules means “the Hero Hercules” in Latin. Its abbreviation is Her and the genitive, used in star names such as β Herculis, is Herculis.
