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Sharpless Sh2-33 - Integrated Flux Nebula in the
constellation of Serpent |
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Short description:
Our image shows Sharpless Sh2-33, a
large molecular cloud that belongs to the type of "integrated flux nebulae"
(galactic cirrus). These are reflection nebulae that, unlike individual stars
or clusters, are illuminated by the integrated energy flow of ALL the
stars in our galaxy. They are concentrated in the direction of the northern and
southern celestial poles and are therefore located far above the disk plane of
our Galaxy.
The classification as
Integrated Flux Nebulae (IFN) goes back to the American amateur astronomer
Steve Mandel. These molecular clouds are extremely faint and Sh2-33 is a rather
rarely recorded example of this type of nebula. IFNs have been little studied
so far because they do not stand out against the image noise of the sky
background in an imperfect dark sky. |
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Another example of such a molecular cloud in the constellation Apus
of us can be
seen here.
Stewart Sharpless (1926 - 2013) was an American astronomer at the
U.S. Naval Observatory who published a catalogue of 313 H-II regions north of
-27 degrees declination in 1959. However, some of the objects listed by
Sharpless are not H-II nebulae but molecular clouds that reflect the light of
all the stars in the Milky Way. They are the so-called Integrated Flux Nebulae,
which Steve Mandel has catalogued in his Unexplored Nebulae Project.
Read more here.
Much information about Steward
Sharpless and his catalogue can be found on the website of the American amateur
astronomer
Dean Salman.
« Click here and or on the thumbnail to load a large image
with object names and size comparison to the moon. |
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All Images und all Content are ©
by Franz Hofmann + Wolfgang Paech |