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Soul Nebula - Latest attempt at processing it


Alex
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Posted by: @Alex

This is my second narrowband image and really struggling to process it. I am currently using PixInsight and might even have to resort to reading the manual !!!!

The image is coming along great. I believe it is just a case of fine tuning on the curves adjustment. The background on this particular nebula is not as dark as most, it is full of nebulosity. I think your background is too dark, and you are removing detail. On my image of this target, the background reading is around 0.1/0.15, I think yours is much lower. Also I think your stars are blown. To compensate against blown stars, and allow you to adjust the image better, use this adjustment in histogram transformation. It can be applied anytime you are getting close to 1.0 on the brightness level. The default is 1.0, adjust to 1.1.

Untitled-1.thumb.jpg.583f836297c7c601bee1cb3094bf25c2.jpg
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Posted by: @AstronomyUkraine
Posted by: @Alex

This is my second narrowband image and really struggling to process it. I am currently using PixInsight and might even have to resort to reading the manual !!!!

The image is coming along great. I believe it is just a case of fine tuning on the curves adjustment. The background on this particular nebula is not as dark as most, it is full of nebulosity. I think your background is too dark, and you are removing detail. On my image of this target, the background reading is around 0.1/0.15, I think yours is much lower. Also I think your stars are blown. To compensate against blown stars, and allow you to adjust the image better, use this adjustment in histogram transformation. It can be applied anytime you are getting close to 1.0 on the brightness level. The default is 1.0, adjust to 1.1.

Untitled-1.thumb.jpg.f79d09abcf5c0ed83ca2ebb0a11b8fbd.jpg

Thanks for the tips :-)

 

I have the nebulosity in the raw data and am definitely clipping the blacks and losing detail. I will try again :-)

 

Do you have a link to your image? Would be interesting to compare

Cheers

Alex

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Posted by: @AstronomyUkraine
Posted by: @Alex

Do you have a link to your image? Would be interesting to compare

Cheers

2099967958_SoulNebula.thumb.jpg.d7778a071838328cbfeba75d52b4c190.jpg

This is my version of the Soul Nebula.

Thanks

I think you were talking about the nebulosity in the top  right of your image?

 

I have that in the raw data just struggling to combine the channels without ending up with a horrible colour cast over the whole image. I think my problem is matching each channel, I have been using the masked stretch and Linear fit

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Posted by: @Alex

I think you were talking about the nebulosity in the top  right of your image?

I have that in the raw data just struggling to combine the channels without ending up with a horrible colour cast over the whole image. I think my problem is matching each channel, I have been using the masked stretch and Linear fit

Yes that bit is more pronounced in mine. Do you have a link to your stacked images. I would like to see if there is any problems with them?

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Posted by: @AstronomyUkraine
Posted by: @Alex

I think you were talking about the nebulosity in the top  right of your image?

I have that in the raw data just struggling to combine the channels without ending up with a horrible colour cast over the whole image. I think my problem is matching each channel, I have been using the masked stretch and Linear fit

Yes that bit is more pronounced in mine. Do you have a link to your stacked images. I would like to see if there is any problems with them?

I have sent you a message with links to the stacked images

 

Thanks

 

Alex

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Posted by: @Alex

I have sent you a message with links to the stacked images

Here is my version of your image. I will list the processes I used.

Dynamic crop

DBE

Linear fit using the Ha stack as reference

Combined the channels into an SHO using Channel Combination

Color calibration, just using a preview for the dark reference, no white reference

Background Neutralization

Stretched the image using ArcsinhStretch with a stretch factor of 35, followed by Histogram transformation

Used Starnet, checking the create star mask box.

Renamed the star mask as RGB stars

After stretching the nebula had a green cast, and the background had a magenta cast. I inverted the image and applied SCNR to remove the magenta, then inverted the image back, and applied SCNR again to remove the green cast.

I worked on the starless image, with curves, using masks to work on the nebula and background. Renamed it SHO

Used TGVDenoise on the starless image

I used the original Ha as a Lum layer. I removed the noise with MultiScaleLinearTransform, then stretched the image as before. Removed the stars using starnet. I tweaked the starless LUM in curves, sharpened it slightly, then combined with the SHO image using LRGBCombination.

Final process was adding the RGB stars extracted from SHO image. I used PixelMath to combine the SHO and RGB stars.

The data is excellent, just need to hone your processing skills a little.

1067099110_SoulNebula.thumb.jpg.900ca7ee5ebfbb088b03053bbb406cac.jpg

 

 

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  • 2 weeks later...
Posted by: @AstronomyUkraine
Posted by: @Alex

Thanks for looking at that - I will try your workflow and see how that goes

Looking forward to seeing your result.

I normally use PhotometricColorCalibration but I didn't know your focal length or pixel size. It might give your stars better colour than the normal ColorCalibration.

Finally had chance to have a play with the data. Following some great help from you its beginning to look a lot better I think. 

 

NGC 2237-261220

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Posted by: @Alex

Finally had chance to have a play with the data. Following some great help from you its beginning to look a lot better I think. 

Yeah, looking really good now, it's a big improvement on your original. You have more detail in the nebula, without over stretching it. Your stars have a green tinge to them, but that should be easy to rectify in curves. If you want to give the nebula a bit more punch, try using the DarkStructureEnhance script, it will give a bit more definition to the dark dust lanes. Another good tool for enhancing detail is the HDRMultiScaleTransform, the default settings are usually fine, but experiment between 5 and 8 layers, to see which gives the best result.

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Posted by: @AstronomyUkraine
Posted by: @Alex

Finally had chance to have a play with the data. Following some great help from you its beginning to look a lot better I think. 

Yeah, looking really good now, it's a big improvement on your original. You have more detail in the nebula, without over stretching it. Your stars have a green tinge to them, but that should be easy to rectify in curves. If you want to give the nebula a bit more punch, try using the DarkStructureEnhance script, it will give a bit more definition to the dark dust lanes. Another good tool for enhancing detail is the HDRMultiScaleTransform, the default settings are usually fine, but experiment between 5 and 8 layers, to see which gives the best result.

Thanks :-)

 

I noticed the green tinge on the stars and removed it after I uploaded the image !

 

Really getting to like PI now

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