M10 - Globular
Cluster in Ophiuchus
M10 - Globular Cluster in Ophiuchus
Mag 6.6, 20 arcminutes across
RA 16 58' Dec -04 07'
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This from SEDS.ORG:
Discovered 1764 by Charles Messier. Messier 10 (M10, NGC 6254) is one
of the bright globulars populating constellation Ophiuchus. This 7th
mag globular cluster appears at about 8 or 9 arc minutes diameter when
observed visually in smaller instruments. Average photos show it at
about 15.1 arc minutes diameter, and deep photos show it to reach out
to about 20 arc minutes, or 2/3 of the diameter of the Full Moon. At
its distance of 14,300 light years, this corresponds to a linear
diameter of 83 light years. Its brighter core which can be seen
visually is only less than half as large, about 35 light-years. It is
receding from us at 69 km/sec. According to Burnham, the extremely low
number of only 3 variables has been found in M10; the ``Catalog of
Galactic Globular Clusters" of R. Monella of the
Sharru Astronomical Observatory, COVO (Bergamo), Italy (ADC/CDS number
VII, 103) gives the number of 4. This globular cluster was discovered
by Charles Messier on May 29,
1764, cataloged as No. 10 in his list, and like most
globular clusters, described as "Nebula without stars" of round
shape. William Herschel was the first to resolve it
into stars.
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Camera: Apogee U16M w Astrodon Gen II LRGB Filters
Telescope: Planewave 12.5 CDK at F/8
Mount: Paramount ME
Guiding: Astrodon MMOAG w SBIG ST-402ME guide camera
Luminance 5 x 5 min
Red 7 x 5 min, Green and Blue 8 x 5 min
Acquired using CCD-Commander, CCDSoft5 and TheSky6 Pro
All images aligned and combined in Maxim
Imported into PS CC with FITS Liberator
Levels and Curves in PS CC, some sharpening followed by Reduce Noise
on background, Gradient removal with Russ Croman's GradX
Click on the image above to see a larger version of the image.
Flesherton, Ontario
June 2014
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