Messier 13, Great Hercules Cluster

   Messier 13 is often called the Great Globular Cluster in Hercules which lies in the constellation
Hercules and considered the most spectacular globular cluster in the northern skies.  It
was discovered by Edmond Halley in 1714 and fifty years later catalogued by Messier.  M13 is about
145 light-years in diameter and contains several hundred thousand stars.  In 1974, because
of its high star density, the Arecibo radio telescope in Puerto Rico transmitted a message
towards M13 for the possibility of reaching extraterrestrials. 


   Globular clusters, and other types of star clusters, should not be taken for granted, for they can
provide worthy photographs to amateurs and professionals.  Patient time-exposure can reveal
colors of the individual stars and high-powered observation can place one's point of view within the
cluster itself and result in realistic three dimensional awareness of being inside a cluster.


{  Photo:  R Lang & Associates }