Tag Archives: M13

The Hercules Cluster

The Hercules Cluster (M13) is located between the two western stars of the Keystone Asterism that represents Hercules’ head. M13 is about 25,100 light years from Earth, and was the target toward which the Arecibo message was beamed in 1974, or 40 years ago. This cluster is comprised of about 300,000 closely packed stars, can be seen with the unaided eye in a very dark sky, and it is easily located with binoculars or modest amateur telescopes. I have not tried, but I think that a camera set up described for the Virgo Cluster could easily capture this cluster.

Hercules (A Roman mythological hero)

HerculesHercules is one of the 88 modern constellations that are among the 48 constellations cataloged by 2nd century astronomer Ptolemy. It is named after the Roman mythological hero adapted from the Greek hero Heracles. It is a northern constellation that lies just off of the Summer Triangle, and near Ophiuchus. Hercules reaches its highest nightfall ascension in July. A squarish asterism called the Keystone is likely to catch the eye first when looking in this area. Older visualizations of this constellation depict the Keystone as Hercules’ hips, while some more modern visualizations depict the Keystone as Hercules’ head.

One of the most notable Messier objects, the Hercules Cluster (M13), is a bright globular star cluster that can be seen with the naked eye in dark skies. It is located between the two stars comprising the Keystone’s western edge. M92 is the only other Messier object in this constellation.  The largest and most massive known structure in the universe, The Hercules-Corona Borealis Great Wall, is a filament of galaxies that is situated on Hercules’ border with Corona Borealis.

IAU Hercules chart, IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg), June 5, 2011.
IAU Hercules chart, IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg), June 5, 2011.

© James R. Johnson, 2014.

The Beehive Cluster (M44)

The Beehive Cluster (M44), in Cancer was the first star cluster that I observed, and it left with me the impression of tiny diamonds on a black felt cloth. Interestingly, M44 is actually brighter than any of Cancer’s stars, but is difficult to see unaided in less than perfectly dark skies. The cluster is located in the center of the constellation, so locate it by looking half way between Pollux and Regulus.