Globular clusters are spherical symmetrical clusters, where the number of stars can range from tens of thousands to one million. In our galaxy we know about 150 similar objects, but we also know globular clusters in other galaxies. These spectacular star groups can also be called the Methuselah of the Milky Way, as they are among the oldest star groups of the age of 10-12 billion. Because of their structure, we can say that it is the most stable star cluster.
The Messier 13 is a globular cluster in the constellation Hercules. With magnitude of 5.8, it could be seen with the naked eye, but it can only be identified as a foggy star. In the middle there is probably no black hole, but some globular clusters has a black hole in the middle. Messier 13 includes about 300,000 stars.
On November 16, 1974, a radio message was sent to this globular cluster using the Arecibo radio telescope. It contains information about humanity, the DNA molecule, the Earth and the solar system. The message will arrive at all globular cluster stars. If there is a response, wait for "only" 46,000 years.
This photo is the result of many short exposures. I had to delete a lot of photos under the sky, because I could only put together the best ones to make the globular cluster so sharp. In the upper left corner, the bluish-colored NGC 6207 spiral galaxy is observed. The brightness of the galaxy is 11.7 magnitude and its distance is 64 million light-years. The tiny spiral galaxy between the galaxy and the globular cluster is the IC 4617. Its distance is about 503 million light-years, with a brightness of 15.2 magnitude.
Messier 13, M13, NGC 6205
R.A. 16 h 41 m 42 s Dec. +36° 27′ 41″
22 181 light-years
20' x 20'
Total exposure time:
Tápióbicske, Pest, Hungary
Nikon D3300 (unmodified)
Sky-Watcher 150/750 mm Newtonian reflector
Sky-Watcher NEQ-5 Pro GoTo
Sky-Watcher f/5 coma corrector
Focal ratio, length:
f/4.5, 682 mm
62 x 30 s
PixInsight, Adobe Lightroom, Adobe Photoshop