M3 – A globular cluster – is an immense ball of half a million stars older than the Sun, held in gravitational embrace by a large black hole (about 5000 solar masses) in the middle. It lies over 30,000 light-years away and is one of about 150 globular star clusters that orbit our Milky Way Galaxy from just above its plane. They are sort of mini-galaxies.
This cluster is about 200 light-years across and is a relatively bright, easy target for binoculars in the northern constellation Canes Venatici, The Hunting Dogs, and not far from Arcturus. I am also putting a highly cropped image of the core of this cluster.
I took this image over 415 minutes. (Luminance 25 images of 10 minutes each, 11 images of each color of 5 minutes).
Cropped image of the core: