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M13 - Globular Cluster in Hercules

Technical card

Imaging telescope or lens: Planewave CDK 12,5'' 12.5 CDK

Imaging camera: QSI 583wsg

Mount: apt1200gto AP1200

Software: CCD Autopilot 5

Resolution: 1100x799

Dates: Feb. 13, 2010

Frames: 24x60"

Integration: 0.4 hours

Avg. Moon age: 28.54 days

Avg. Moon phase: 1.11% job: 1511801

RA center: 250.420 degrees

DEC center: 36.457 degrees

Pixel scale: 1.229 arcsec/pixel

Orientation: 90.101 degrees

Field radius: 0.232 degrees

Locations: ImagingInfinity Observatory, Bethune, SC, United States


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.



Hap Griffin

Sky plot

Sky plot


M13 - Globular Cluster in Hercules, Hap Griffin