Great globular cluster in Hercules is huge, it contains approximately 300 000 stars and it has about 145 light years in diameter and it is 25 thousands of light years away from the solar system. In 1974 a message from Earth was sent to M13 inhabitants, but due to the speed of light will be received after 24,959 years (Arecibo message).

M13_2015-09-08-30C-180s-10L-120s-6RGB-FL730

Telescope:Newton 254/1000 mm
Aperture:254 mm
Focal length:730 mm
MountGemini GF53f
AutoguidingZWO 174MM, TS 60/240 mm
Camera:Moravian instruments G2 8300M @-30C
Corrector:ASA 2" reducer 0.73
Filters:Baader LRGB
Exposure:10xL 180 s bin 1x1, 6RGB, 120s, bin 2x2
Date:2015-09-08