Hercules (constellation)

Tau Herculids

  • Dragon
  • Bootes
  • Northern Crown
  • Snake (head)
  • Ophiuchus
  • Eagle
  • Arrow
  • Lyre

The Herkules ( Hercules in Latin ) is a constellation of the northern sky.


The Hercules is the fifth largest constellation in the sky. Since only three of its stars are brighter than the third magnitude, it is, however, not very noticeable. It is found between the constellation Lyra with the bright star Vega and the catchy Northern Crown. The best time to look is the early summer, as he is highest in the sky.

The Hercules contains two interesting globular clusters, which can be observed with binoculars already.

In the direction of Hercules is the apex of our solar system. The sun and its planets move relative to its neighboring stars, at 20 km / s on these " target " to.


The constellation is one of the classic 48 constellations of the ancient world, mentioned by Ptolemy. For the ancient Greeks, however, he was simply called " Engonasin " ("The Kneeling "). Later, like Prometheus, Theseus, Orpheus or Hercules the constellation with different mythical figures have been associated, ( whom the Romans called Hercules ). Has received the interpretation as Hercules.

To Johannes Hevelius in 1687 summed up some stars between Hercules and the swan to the constellation of Cerberus, the three-headed hound of hell together. However, it did not sit through.


The mythological origin of the constellation is unclear. Has obtained the subsequent identification with Heracles, which is equipped with giant forces heroes of Greek mythology. Heracles was an illegitimate son of Zeus, the twelve actually insurmountable tasks are delegated. He was able to fulfill the tasks which it took away some monsters to the track, which are also immortalized in the sky, like the lion, the cancer, the water snake and the dragon by power and intelligence.

Celestial objects


β Herculis, the brightest star in Hercules, is a yellowish shining star of spectral type G8 in 148 light years away. The ancient Greek name Kornephoros means " mace bearer ". The star is also known as Ruticulus.

μ Herculis is 27 light years away. It has about 1.1 times the mass of our sun and also light yellowish.

Double stars

α Herculis, the third brightest star in Hercules, is a double star system 430 light-years away. The main star is of spectral type M5 a red giant, with 500 times the diameter and 830fachen luminosity of our sun. Its surface temperature is relatively low at about 3000 Kelvin. Much of his radiation it emits in the infrared. The companion star belongs to the class G5. The system can be separated into individual stars already in the smaller telescope and shows a very nice color contrast. The main star is lit orange, the companion star will appear greenish. The name Ras Algethi is of Arabic origin and means something like " the head of the kneeling man ."

Variable Stars

The main star of the system Ras Algethi is a semi- regular variable star whose brightness varies over periods of 90 to 100 days.

68 (u ) Herculis is a variable star of type beta Lyrae. It is an extremely luminous star in 1200 light years away.

Messier and NGC objects

M13 is considered the most impressive globular clusters of the northern sky. It is located about 25,000 light- years away and consists of about 300,000 stars. Already in a prism binoculars it appears as a misty spot. In a telescope it can be resolved into individual stars. It is easy to find, as he η in the upper third of the line connecting the stars and ζ (the right " box stars " of Hercules ) is.

M92 is a globular cluster about 30,000 light years away. He appears in the telescope is not quite as extensive as M13, but is also a very worthwhile observation object.

NGC 6210 is a planetary nebula in 3,000 light- years away. With a diameter of 0.3 arc minutes, he is not very extensive. In binoculars it appears only as a faint star. In a telescope of 12 cm aperture an irregular slices and the central star is visible.


The exoplanet HD 149026 b in the Hercules is equipped with a temperature on the day side of over 2000 K one of the hottest exoplanets. It orbits the star HD 149026 ( 8.15 likes spectral class G0, 1.3 solar masses ) seen in 2.87 days at 0.042 AU distance and performs one of us from a transit. The exoplanet has a mass of about 0.4 Jupiter masses and a radius of about 0.7 Jupiter radii. The system is about 260 light-years away from Earth.