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It has been cloudy for the past 2 nights in the observatory, halting Messier Object observation for a short while. At around midnight, fortunately, the night sky cleared out and had a chance to image one prominent star cluster.

For today’s observation log, here is the Great Globular Cluster in Hercules (also known as Messier 13, or NGC6205) taken from Al Sadeem Observatory using Meade LX850 16″ SCT and SBIG STT-8300MM CCD camera.

With an apparent magnitude of +5.8, it is considered one of the brightest star clusters seen in the night skies of areas situated in the Northern Hemisphere. This globular cluster consists an intermediate concentration of about 300,000 stars spanning about 84 light-years in radius, located about 22,200 light-years away from Earth.

This globular cluster is best seen during spring and summer season in the northern hemisphere (March-September). It can be seen with the naked eye as a faint fuzzy star under clear and extremely skies. More details will be revealed using binoculars and small amateur telescopes (appearing as a comet-like hazy patch of light with a bright center) and numerous stars being resolved using bigger-aperture telescopes. The red giant variable star, V11, having an apparent visual magnitude of 11.95, is the brightest one to be seen within the cluster.

The cluster within the faint “keystone” asterism of the Hercules constellation, lies about 1/3 distance between the brilliant stars Vega (bluish-white star in Lyra) and Arcturus (reddish-orange star in Arcturus). Simplicity speaking, just scan the region in between the two upper-mentioned stars on the western side and you may be able to find this fuzzy patch of light.

In 1974, an encoded “message” containing information about the human race, DNA, and Earth’s location in the universe was sent to M13 by astronomers from the Arecibo Observatory radio telescope as an experiment for contacting possible extraterrestrial civilizations.

Location of the Great Hercules Cluster in the sky (Credit: Starry Night Software)

REFERENCES (2018). Messier 13. [online] Available at: [Accessed 14 Apr. 2018].

Plotner, T. (2018). Messier 13 (M13) – The Great Hercules Cluster – Universe Today. [online] Universe Today. Available at: [Accessed 14 Apr. 2018].

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