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Messier 19, NGC 6293 and Barnard 59 - Globular Cluster and
dark cloud in the constellation Ophiuchus |
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Object description:
All three objects are located in the constellation
Ophiuchus. Messier 19 (NGC 6273) is a
globular cluster assigned to class VIII according to Shapley, which means that
it is loosely concentrated towards the center. It has the respectable apparent
size of 17 arcminutes. The distance to the Sun is estimated to be about 28 000
light-years and from this follows a physical diameter 110 to 150 light-years.
The age of the cluster's stars is estimated to be about 12 billion
years.
The cluster contains a number of variable stars, including
Cepheids and RV Tauri-type stars, and at least one RR Lyrae-type variable with
a known pulsation period. Messier 19 is one of the most oblate globular
clusters known (compare its shape with NGC 6293). It has a distinctly elongated
shape in the north-south direction. The flattened appearance may not accurately
reflect the physical shape of the cluster because of intervening dust and gas
along the eastern edge of M19. M19 was discovered by Charles Messier on June 5,
1764. |
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NGC 6293, also a globular
cluster, but much smaller than M 19, is assigned to class
IV according to Shapley. The cluster is nearly 30 000 light-years away
from the solar system and was discovered by Frederick William Herschel on May
24, 1784.
Barnard 59
(LDN 1740) is a smaller dark cloud from the
Barnard catalog. About half a degree east of NGC 6293 begins the large dark
nebula region known as the pipe Nebula. We show a
wide angle view of the region
here.
« Click here or the thumbnail to load a large annoted image
and a size comparison to the full moon. |
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All Images and all Content are ©
by Franz Hofmann + Wolfgang Paech |