Info from Wikipedia:
With an apparent magnitude of 5.8, (M13) is barely visible with the naked eye on a very clear night. Its real diameter is about 145 light-years, and is composed of several hundred thousand stars, the brightest of which is the variable star V11 with an apparent magnitude of 11.95. M13 is 25,100 light-years away from Earth.
Nice to catch a few photons after the long cloudy spell.
10" LX200 @ f/6.3, 20 x 60 sec, EOS 350 D @ 1600 ISO