M13 is a beautiful globular cluster of around 300,000 stars in the constellation of Hercules.
This was actually the first cluster that I observed visually and later on actually imaged (see below).
The distances involved with M13 are pretty impressive too. M13 is 25,100 light-years away from Earth and is 145 light years across !
As an interesting science experiment heading towards the M13 is the ‘Arecibo Message‘.
20s x 20 Light subs + dark & bias frames.