M13 - Globular Cluster in Hercules 


Copyright 2007 Frank Hinson

M13 is the best known of a class of objects called globular star clusters.  They are generally groups of several hundred thousand stars in a distinctly spherical shape that occupy a halo region around the central bulge of spiral galaxies, such as our own Milky Way galaxy.  They also are some of the oldest objects in the universe based on studies of the concentrations of elements within the constituent stars.  In the cores of such clusters, the stars are more than 500 times closer together than in normal space.

  M13 lies at a distance of 25,100 light years.  It is visible by the naked eye from dark sky locations as a very faint smudge along one edge of the "keystone" of stars in the central part of the constellation Hercules.  In 1974, M13 was selected to be the target of the first radio message to possible extraterrestrial civilizations intentionally beamed into space from the large radio telescope in Arecibo, Puerto Rico.


Date/Location:    May 26, 2007     Foster/Hinson Observatory    Bethune, SC
Instrument:    Canon 350XT Digital SLR (modified) through 12.5" F/5 Newtonian 
Focal Ratio:   F/5
Guiding:    None - AP1200 mount
Conditions:    Visually clear
Weather:    60 F
Exposure: 120 minutes total (60 x 2 minutes)
Filters:    Baader UV/IR Block
Processing:    Focused and captured with DSLRFocus.  Processing in ImagesPlus and Photoshop.