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The region around M 8, M 20, M 21 and IC 1274/75 - a 4 frame
mosaic taken with a focal length of f = 670 mm |
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Object description:
Detailed object description and higher resolution
images of Messier 8
are shown here.. Detailed object description and higher
resolution images of Messier 20
are shown here..
Messier 21 is an open star
cluster with an apparent diameter of 15 arcminutes. It is classified by
Trumpler as type I 3 m. The cluster contains about
60 stars, exceptional is a concentration of blue B supergiants in the core
region. Because of these stars, which have a lifetime of only 10 to 15 million
years, the age of M 21 is estimated to be about 4.5 million years.
The
distance to the solar system is only vaguely known, the information varies
between 2000- and 4000 light-years depending on the source. Depending on the
assumed distance the physical diameter of M 21 is 8 or 16 light-years. The star
cluster was discovered by Charles Messier on June 5, 1764.
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IC 1274, IC 1275, IC 4685 und NGC
6559 are H-II emission nebula regions intermixed with blue
reflection nebulae. IC 1274/75 are also cataloged as LBN 33. The entire region
is part of the large molecular cloud Lynd 227. The nebular region was first
described by Edward Emerson Barnard on June 25, 1892.
IC 1274 contains a young open star cluster with 4
blue giant stars. For the whole region a distance of about 6000 light years is
given and thus the nebular region is about 800 to 1000 light years farther away
from the solar system than the Lagoon Nebula Messier 8. A detailed description
of the nebular region
can be found here.
« Click here or the thumbnail to load a large annoted image
.Source:
https://iopscience.iop.org/article/10.1088/0004-6256/143/1/3 |
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NGC 4546 is an open star cluster,
classified as III 2 m by Trumpler. It contains
about 150 stars and its distance to the solar system is given as about 3000
light-years. NGC 6546 was discovered by John Herschel on June 27,
1837.
NGC
6544 NGC 6544 is a small globular cluster, classified by Shapley as
Type V. It stands about 10,000 light-years from the solar system and was
discovered by Friedrich Wilhelm Herschel on May 22, 1784. A detailed scientific
study
can
be found here.
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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 und all Content are ©
by Franz Hofmann + Wolfgang Paech |