Messier 13

With an apparent magnitude of 5.8, it is barely visible with the naked eye on a very clear night. Its diameter is about 23 arc minutes and it is readily viewable in small telescopes. M13 is about 145 light-years in diameter, and it is composed of several hundred thousand stars, the brightest of which is a red giant, the variable star V11, with an apparent visual magnitude of 11.95. M13 is 25,100 light-years away from Earth. More on Wiki

Image details:
Telescope: TS 90/600 triplet with 2.5" TS flattener
Mount: Skywatcher az-eq 5
Camera: Atik one 6.0
Exposure: 100 * 300sec L.
Software: PixInsight
Calibrationfiles: Dark:No, Bias:Yes (masterbias), Flat:Yes

(c) All photos by Ruud de Vries