Messier 13 (M13), also designated NGC 6205 and sometimes called the Great Globular Cluster in Hercules or the Hercules Globular Cluster, is a globular cluster of about 300,000 stars in the constellation of Hercules. M13 is about 145 light-years in diameter, and it is composed of several hundred thousand stars, the brightest of which is the variable star V11 with an apparent magnitude of 11.95. M13 is 25,100 light-years away from Earth.
M13 was discovered by Edmond Halley in 1714, and catalogued by Charles Messier on June 1, 1764. It is located at right ascension 16h 41.7m and declination +36° 28′. With an apparent magnitude of 5.8, it is barely visible with the naked eye on a very clear night. Its diameter is about 23 arc minutes and it is readily viewable in small telescopes. Nearby is NGC 6207, a 12th magnitude edge-on galaxy that lies 28 arc minutes directly north east. A small galaxy, IC 4617, lies halfway between NGC 6207 and M13, north-northeast of the large globular cluster’s center.
Imaging telescopes or lenses: AT6RC
Imaging cameras: Canon EOS 1000D / Rebel XS
Mounts: Orion Atlas EQ-G
Guiding telescopes or lenses: Orion Mini Guide Scope
Guiding cameras: Orion Star Shoot Planetary Imager & Autoguider
Focal reducers: TeleVue 0.8x
Software: DeepSkyStacker, PHD guiding, photoshop, Canon EOS
Accessories: DIY thermoelectric camera cooler
Dates: June 9, 2012
Locations: Elkins, WV
Integration: 2.4 hours
Autor: Mike Carroll
09 March 2014
We select the best works of amateur astrophotographers with details of equipment, shooting processing etc.