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NGC 7009 - the Saturn nebula |
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For this
image of the Saturn Nebula, the worst images were sorted out from 1000 images
in each of the colour channels. The remaining images are almost 600 frames
through the red and green filter, as well as almost 900 frames for the blue
channel. The seeing in the stacked images reached values around 2.1''. The
almost full Moon was only between 15 and 45 degrees away from NGC 7009 during
the exposures. |
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Object description:
The Saturn Nebula (NGC 7009) is a planetary nebula in
the constellation Aquarius and is located in a distance of about 5000 light
years from the solar system. It was discovered on 7 September 1782 by Friedrich
Wilhelm Herschel. The name was given by Lord Rosse because the shape of the
jets reminds him of Saturn's rings.
Planetary nebulae have nothing to
do with planets. This term was introduced by Herschel because the similarity of
these often unstructured objects with the planet Uranus.
« Click here or the thumbnail image for a comparison with the
size of the Moon
The physical
formation of planetary nebulae is principally understood today. The Saturn
Nebula was originally a star of low mass. Towards the end of its life, it
expanded into a red giant star and repelled its outer gas layers. The remaining
one, extremely hot (50,000 K), core of the star causes the gas layers to light
up in colour due to strong ultraviolet radiation. The star has |
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developed
into a white dwarf star, which is clearly visible in our image. Double ionized
oxygen is responsible for the characteristic fluorescent green of the nebula.
The diameter of the Saturn Nebula is about 0.5 light years. It lies in a very
starless region and seems to "float in nothingness".
Our sun will maybe suffer a similar fate in about 4.5
billion years at the end of its life and will also produce a colourful
planetary nebula.
A high-resolution image of the Hubble Space Telescope
from the Saturn Nebula can be found
here and a detailed object description with many ESO images
here. |
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