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).
| Telescope: | Newton 254/1000 mm |
| Aperture: | 254 mm |
| Focal length: | 730 mm |
| Mount | Gemini GF53f |
| Autoguiding | ZWO 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 |
[…] my opinion, Messier 13 is the most beautiful globular cluster in our galaxy. Last time when I photographed this cluster, I used focal reducer (don’t ask me why), therefore I decided to recapture it with focal length […]