The first "test image" of the home-made 200/800 mm Newtonian reflector was chosen a globular cluster in the Hercules constellation. Many people would surely be thrilled to pick Messier 13, but it wasn't. On July 15, 2018, I turned my reflector toward an undeservedly neglected globular cluster.
At 9.5 degrees from the M13, there is a very bright and glittering globular cluster that is also located in the Hercules constellation. This globular cluster is the object 92 of the catalog of the French astronomer Charles Messier, which has a relatively smaller apparent diameter than the M13, but I believe in the spectacle that it will compete with it.
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.
Messier 92 is also old among globular clusters, as it is almost the same age as the universe. Estimated that it may be 14.2 ± 1.2 billion years old. A mass of 330,000 solar masses, with the M13 approx. half-millionth of its weight is also below. Astronomers are know to more than a dozen longer-term RR Lyrae-type variables in the cluster, but many X-ray sources have been discovered in it. The cluster is getting closer to us by 112 kilometers per second, but of course, there is no reason to worry about 26,748 light-years away. However, it will be an important object for future amateur astronomers for 14,000 years, as the precession of the celestial poles will place only two degrees from the northern pole.
Interestingly, more than three years before Messier was discovered, in December 1777, German astronomer Johann Elert Bode made a note about the object. Nowadays, they both accept independent explorers.
The environment of the cluster is full of small galaxies. At the edges of the image (mainly to the left of the globular cluster) there are several relatively small and faint star cities. These are the most well-known: NGC 6329, NGC 6332, NGC 6336, NGC 6344, IC 4645. In addition, a number of 15-16 magnitude PGC catalog galaxies appear.
I managed to capture a clear, moonless sky to take the photo. All the circumstances favored the quality of the image. Due to the short summer nights and my possibilities, I only made the capture with one hour of exposure, but I am about to return to this unworthily neglected sphere and its wonderful environment.
Messier 92, M92, NGC 6341, Mel 168
R.A. 17 h 17 m 07 s Dec. +43° 08′ 09″
26 748 light-years
14' x 14'
Total exposure time:
Tápióbicske, Pest, Hungary
Canon EOS 1300D (unmodified)
Home-made 200/800 mm Newtonian reflector
Sky-Watcher EQ6-R Pro GoTo
Sky-Watcher f/4 coma corrector
Focal ratio, length:
f/4, 800 mm
60 x 60 s
PixInsight, Nebulosity, Adobe Lightroom, Adobe Photoshop
While taking the photo, on July 15, 2018, at 22:47 UT, the Atlas Air airline Frankfurt - Kuwait passed the image. The position indicator and the flying back wings left a trace on the exposure.