Constellation - Hercules

Constellation - Hercules


Hercules is the fifth largest constellation and was one of the original 48 constellations described by Ptolemy. He stands on the head of the snake constellation, Draco. The main part of the constellation is the asterism 'keystone' that makes up the keystone shaped square area in the middle. In this part of the constellation can be found the fantastic "Great Globular Cluster" or M13. One of the wonders of the night sky that must not be missed.


Hercules was the son of Jupiter. In Greek mythology he was named Heracles and was the son of Zeus. He was famous for his legendary strength. He was placed in the sky after his completion of the twelve labours, a list of quests that included killing the Nimean lion whose pelt was impervious to weapons, slaying the Hydra and stealing the apples of Hesperides. 

Take the Tour:

Number Object Description Magnitude Surface Brightness
1 M13 Globular Cluster 5.9 12
2 M92 Globular Cluster 6.5 11

Each image is the size of a full moon for size comparison.

M13, The Great Globular Cluster of Hercules:


Messier 13, or the Great Globular Cluster of Hercules is found about 22,000 light years away. It was discovered by Edmond Halley in 1714. This is one of the jewels of the night sky. Visible to the naked eye on a dark night. It is a large globular cluster 145,000 light years across. This cluster is unusual in that it contains a young blue star amongst all the old stars in the cluster. The star was probably collected by the cluster as it moved around the galaxy. Also, the arecibo message was sent to M13. This is the message that detailed the existence of human beings. Unfortunately, by the time the message reaches the cluster it will no longer be in its current position. So, if there are any intelligent beings living amongst the great globular cluster they will never know of our existence.



Messier 92 is a globular cluster found 27,000 light years away. It was discovered by Bode in December 1777. This is an easily seen globular and would be a candidate for one of the best globulars if it wasn't upstaged by the so near M13. M92 is one of the oldest globulars known with estimates of its age being about the same as the age of the Universe.

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