Globular Clusters
Globular Clusters are star clusters with a high central concentration of stars and a spherically symmetric distribution, and with diameters of 100 to
150 light years. Normal galaxies contain several hundred globular clusters. The haloes of giant elliptical galaxis such as M 87 contain, however, up to 10000 globular clusters.
Globular clusters are formed during gravitational merging of galaxies, a process in which huge areas of condensed gas are formed, which gives rise to extremely strong star formation.
M 13 (NGC 6205)
Maksutov-Newton, Canon 1100Da,
29 minutes
Globular clusters consist of about 100.000 stars which are kept together by their mutual gravitation, thereby forming stellar systems with an extent of about 100 ly. In contrast to open clusters, their stars are bound together by their common gravitational forces. Globular clusters are created during galaxy formation or shortly thereafter, and hence they are very old - essentially as old as the visible universe. M 13 is about 25,000 ly distant. This cluster is well visible in any binocular, and even with the naked eye in good sky conditions! In the lower left of the image one can see a distant (nearly 50 million ly) galaxy.
M 15 (NGC 7078)
Maksutov-Newton, Canon 1100Da,
90 minutes
This globular cluster is about 30,000 ly distant. When searching for it with the binocular one needs a little bit of patience, as it is not quite as bright as the other two shown here.
M 92 (NGC 6341)
Maksutov-Newton,
Canon 1100Da,
51 minutes
This globular cluster can be easily seen with a binocular. It is 20.000 ly away from us. The three globular clusters shown here are well visible in a small telescope, and in my early obserations with my telescope I frequently used these objects to check the positioning of my telescope.
M 3 (NGC 5272)
Maksutov-Newton, Canon 1100Da,
30 Minuten
Also this globular cluster is readily found with a binocular. M 3 is about 34000 light years distant.
M 5 (NGC 5904)
Maksutov-Newton, Canon 1100Da,
30 Minuten
Also this globular cluster is readily found with a binocular. M 5 ist about 24500 light years distant.