the hero Hercules · pronounced HER-kyuh-leez. Hercules is a large northern constellation whose central Keystone asterism provides the easiest entry point. It occupies the sky between Boötes, Corona Borealis, Lyra and Ophiuchus and is best placed on Northern Hemisphere summer evenings. Ptolemy catalogued the figure among the ancient 48, but earlier Greek texts knew a kneeling figure without always identifying him; the association with Heracles and his labours became standard later. The constellation’s stars are not exceptionally bright, yet it contains M13, the celebrated Great Globular Cluster, visible in binoculars under good conditions along one side of the Keystone. M92 is another excellent globular, while the Hercules Galaxy Cluster offers a much more distant telescopic field. Ras Algethi is a colourful multiple star near Ophiuchus. The solar apex—the direction of the Sun’s motion relative to nearby stars—lies in Hercules. The Keystone is an informal asterism inside the official IAU region, not a separate constellation. Cultural star figures crossing the same area require individual context rather than being described simply as versions of Hercules.
About Hercules
Hercules is one of the 88 constellations recognized by the International Astronomical Union. Its standard three-letter abbreviation is Her, and astronomers use the genitive form Herculis when naming stars associated with it. The constellation's reference position lies around right ascension -7.1 hours and declination +35 degrees.
Its location places it in the northern sky. For a typical mid-latitude observer, this part of the celestial sphere is especially well placed during spring evenings. Exact visibility depends on latitude, local horizon, date and time.
History and mythology of Hercules
Historical origin
Ptolemy catalogued the figure among the ancient 48, but earlier Greek texts knew a kneeling figure without always identifying him; the association with Heracles and his labours became standard later. The constellation’s stars are not exceptionally bright, yet it contains M13, the celebrated Great Globular Cluster, visible in binoculars under good conditions along one side of the Keystone.
The modern constellation
Hercules became one of the 88 official constellations standardized by the International Astronomical Union. Its boundary is a coordinate-defined sky region, while the familiar line figure joins only selected stars and has no physical depth.
Reading the cultural record
Names and stories attached to this part of the sky changed across languages, periods and communities. Cultural parallels should be identified from specialist sources rather than presented as interchangeable versions of Hercules.
How to find Hercules
- Use a location-aware chart and observe when Hercules reaches its highest evening altitude; check that the full constellation rises from your latitude.
- Locate Kornephoros, magnitude 2.8, then compare its direction with a brighter neighboring constellation rather than relying on line art alone.
- Trace the main pattern toward Zeta Herculis; binoculars reveal the fainter connecting stars while preserving a wide field.
- Move to M13 with a low-power eyepiece or binoculars, then increase magnification only if its surface brightness permits.
Bright stars in Hercules
Kornephoros
Notable star- Magnitude
- 2.8
- Distance
- 139 ly
A yellow giant and the constellation’s brightest star despite carrying the beta designation.
Zeta Herculis
Notable star- Magnitude
- 2.8 combined
- Distance
- 35 ly
A nearby binary on a corner of the Keystone.
Ras Algethi
Notable star- Magnitude
- variable about 3–4
- Distance
- about 360 ly
A red supergiant primary with a visually contrasting companion near Ophiuchus.
Pi Herculis
Notable star- Magnitude
- 3.2
- Distance
- 377 ly
An orange giant marking the Keystone’s northeastern corner.
Deep-sky objects in Hercules
M13
The Great Hercules Cluster contains hundreds of thousands of old stars and is visible in binoculars.
M92
A compact, metal-poor cluster nearly as impressive as M13 in a telescope.
Abell 2151
The Hercules Cluster contains interacting spiral and elliptical galaxies roughly 500 million light-years away.
NGC 6210
A small, bright planetary nebula with a high-surface-brightness inner shell.
Interesting facts about Hercules
- Hercules’s traditional name refers to hero hercules, while its official IAU boundary defines a precise region of the sky.
- Kornephoros, at magnitude 2.8, is a key star in Hercules. A yellow giant and the constellation’s brightest star despite carrying the beta designation.
- M13 is a notable globular cluster in Hercules. The Great Hercules Cluster contains hundreds of thousands of old stars and is visible in binoculars.
- M92, a globular cluster, is another observing target within the constellation.
- Ptolemy catalogued the figure among the ancient 48, but earlier Greek texts knew a kneeling figure without always identifying him; the association with Heracles and his labours became standard later.