The M 5 Globular Cluster in Serpens spanning 165 light-years in diameter is one of the largest known globular clusters.
At about 12 billion years M5 is also one of the eldest globular clusters in our Milky Way Galaxy.
Its distance is about 24,500 light-years from Earth, and it is estimated to contain between 100,000 and 500,000 stars,
the brightest ones are shining at mag 12. Its diameter of 23 arc-min is filling the field of the CCD chip. The overall magnitude is 6.
A lot of faint background galaxies are shining through the cluster.
Image data:
LRGB (200-120-120-120 min) total 9,3 h, north is up, seeing 0.8-1.2 arc-sec,
80cm f/7 Astrooptik Keller cassegrain, FLI PL-16803, Astrodon gen2 filters, Prompt 7 CTIO Chile
Processing: Johannes Schedler
Find below the full image in 25/75% size.