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Messier 12 (Ophiuchus)

Object image
Fig.1 - With an unusually low number of low-mass stars: Messier 12 (NGC 6218) in Ophiuchus, photographed with a 16-inch f/4.5 Dob on an equatorial platform.
Object name: Constellation: Coordinates: Apparent size: Visual brightness:
Messier 12
(NGC 6218)		 Serpens 16h47m / -01°57' 16' 6.1 mag

The globular cluster Messier 12 (NGC 6218, Gumball Globular) in the constellation Ophiuchus. Messier 12 is approximately 16,000 light-years from Earth, measures about 75 light-years in diameter and was discovered by French astronomer Charles Messier in 1764. The cluster contains about 200,000 stars and is only loosely packed (source: Wikipedia).

Twenty-four 3-minute exposures (72 minutes total exposure) at gain 100 and -10°C, taken on June 10 / 11, 2023, were added for this shot with Astro Pixel Processor (APP) software and the final image processing was done in Photoshop. Darks, flats, darkflats and bias frames were used.

Equipment: Cooled ASI 2600MC Pro camera, TeleVue Paracorr Type II coma corrector, 16" f/4.5 "Ninja" dobsonian telescope riding on a dual-axis Tom Osypowski equatorial platform, Lacerta MGEN autoguider, Lacerta off axis system (field of view comparison: image of the moon with the same equipment).

Object image
Fig.2 - Another representation of Messier 12 (NGC 6218) in Ophiuchus, photographed with a 16-inch f/4.5 Dob on an equatorial platform. In addition to the twenty-four 3-minute exposures from June 10 / 11, 2023, seventy 1-minute exposures from July 8 / 9, 2023, have been used for this mosaic (142 minutes total exposure). A pair of distant galaxies shines through the globular cluster, the brighter of the couple being PGC 1103219 (15.8 mag), 870 million light-years from Earth.
Search chart
Fig.3 - Search chart for Messier 12. Map © 2023 "The Mag-7 Star Atlas Project", www.siaris.net. Map is slightly modified. The map can be downloaded here.
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