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NGC6960 cirrus on fire

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wvandenberghe:
Hello Everyone

I'd like to present my latest image of the cirrus nebula :
http://www.vstobservatory.net/gallery/nebula/NGC6960.htm


Processing done with Pixinsight:
R: 18x10min G: 18x10min B: 18x10min with RCOS truss 14,5" f/9 telescope + SBIG STL11000M, data of last 3 nights was very good , 20.6magnitude/arcsec^2 background sky level.

preprocessing script + cosmeticcorrection
Linear Fit Clipping Integration of R,G,B

DBE 10 samples 8 size
Make previews on starfields without nebulosity
Aggregate previews script
ColorCorrection on aggregated stars as white reference and structure detection on, backround reference is also aggregated stars
RGBWorkingspace RGB 0.33 0.33 0.33
extract Lum mask from rgb
auto stf on lum mask,apply to HistogramTransformation and invert mask, apply to RGB
MMT noise reduction 4 layer , layer 1 Threshold 3 adaptive 1 layer 2 threshold 1 adaptive 0.5
SCNR green noise remove Protection : maximum neutral
ACDNR noise reduction only in chrominance with Standard Deviation about 3.5 , Lightness mask applied with 2 removed wavelet layers.
CurvesTransformation on RGB/K
Extract Luminance mask from RGB, apply mask  to RGB
CurvesTransformation  Saturation "contrast" curve

Comments & critiques very welcome
Wolfgang
www.vstobservatory.net
Belgium

mschuster:
Hi Wolfgang,

Would it be possible to generate and present an uncompressed .png image (should be about 7.5mb in size)? I am thinking that the .jpg file compression has introduced artifacts in the background.

Thanks,
Mike

wvandenberghe:
Mike
Where would these irregularities be?
Cannot see where they are.
If you could show me?
txs
Wolfgang

mschuster:
Hi Wolfgang,

Check out the attached image. It is a 128 x 128 pixel clip from the upper left corner of your image converted to gray scale and stretched. You can see evidence of excessive .jpg compression in the 8 x 8 pixel blocks, some are blurry and others have various horizontal and vertical line artifacts. Using .png or increasing the .jpg quality setting should fix the problem.

Regards,
Mike

wvandenberghe:
well, you spotted the STL11000 vertical artifacts.

I would be glad if someone from pixinsight.com had a good image processing routine to get rid of them, because a change in CCD in no option.

regards

Wolfgang

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