Globular Cluster in Ophiuchus

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The constellation Ophiuchus, the serpent bearer, is rich in globular clusters, and eight of them made it onto Messier's list. At an estimated distance of about 15,000 light years, Messier 10 is the closest of these eight. It is a good target for summer viewing. Individual stars are well resolved with telescopes of moderate aperture.

About 3 degrees to the northwest is Messier 12, another globular cluster of similar brightness.

Magnitude 6.6
Apparent Size 15'
Distance (light yrs) 15,000
Right Ascension 16:57.1
Declination -4 05
Field of View 29' x 22'

Image details:  Exposure times of 48 minutes luminance, 18 minutes each of red, green, and blue, taken with an SBIG ST-8300M imager and a 14" Meade LX850 telescope at f/6.

July 2014