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Monday, June 28, 2010

NGC 6357, Sharpless 11

HST-palette from the emission of ionized elements, R=Sulfur, G=Hydrogen and B=Oxygen

Natural color composition from the emission of ionized elements, R=80%Hydrogen+20%Sulfur, G=100%Oxygen and B=85%Oxygen+15%Hydrogen to compensate otherwise missing H-beta emission.
This composition is very close to a visual spectrum.

NGC 6357 locates in constellation Scorpius and it's know by names Sharpless 11, RCW 131 and Gum 66.

Looks very much like an Egyptian Horus!

The telescope and technical information:

16" RCOS ja Apogee U9000 camera. 
LRGB combo.
H-alpha 4x1200s, Dark and artificial Flat calibrated.
1xO-III 1200s, Dark and artificial Flat calibrated.
1xO-III 1200s, Dark and artificial Flat calibrated.
Raw data is shared with "Team Finland"

Processing workflow:
Image acquisition, MaxiDL
Stacked and calibrated in CCDStack.
Deconvolution with a CCDSharp, 30 iterations
Levels, curves and color combine in PS CS3.

A Starless version to show the actual nebulous.
In my processing technique, the starless image is used as a color map for HST-palette balancing.
Now and then I publish an image with a suppressed stars, since it can look kind of nice/spooky.

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