Globular Cluster in Ophiuchus
Messier 9 is a densely packed globular cluster. Compare its appearance to my image of Messier 10. These two clusters actually have about the same diameters, but Messier 10 is closer to us, and it is a more impressive sight in amateur telescopes. However M9 is estimated to have about twice the mass of M10, due to its greater density of stars.
There are many stars of the Milky Way in the background, but fewer are visible in the lower right corner of this image. This because M9 is bordered to the southwest by a dark nebula, Barnard 64, which obscures the light of the stars beyond it.
| Magnitude | 7.7 |
| Apparent Size | 9' |
| Distance (light yrs) | 26,000 |
| Right Ascension | 17:19.2 |
| Declination | -18 31 |
| Field of View | 22' x 17' |
Image details: Exposure times of 42 minutes luminance and 24 minutes each of red, green and blue, taken with an SBIG 8300M imager and a 14" Meade LX850 telescope at f/8.
July 2018