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Barnard 253, Barnard 63 and other dark nebulae in the
constellation of serpens |
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Object description:
Our image shows the large dark cloud
Barnard 253 almost in the center of the
image. In the constellation of the Serpens there are numerous dark nebulae with
different optical transmittances. Barnard 253 appears about as large as the
moon in the sky and still lets some of the light of the stars behind it pass.
Barnard 63 (partially visible at the top of the
image) contains so much gas and dust masses that no light can pass through the
nebula in the optical range.
In the constellation of the Serpens there
are numerous, large dark clouds, which were first catalogued photographically
by the American astronomer Edward Emerson Barnard. The complete catalog of over
300 dark clouds by Barnard
can be found at this URL. Barnard was self-taught and one
of the pioneers of astrophotography. In more recent times, detailed studies by
K. Dobashi in infrared light followed.
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Dark
clouds or dark nebulae are large collections of interstellar matter that either
absorb the light of stars behind them (e.g. the Coal Sack) or cover parts of
H-II regions or reflection nebulae (e.g. Barnard 33, the Horsehead Nebula in
the constellation Orion).
The
shape of such dark clouds is usually irregular and without clearly defined
outer boundaries. Many of the dark clouds have proper names, like the Snake
Nebula or the Pipe Nebula. The image shows impressively the different densities
of the dark nebulae.
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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 |