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Contains:  M 43, NGC 1982, NGC 1980, M 42, Great Nebula in Orion, NGC 1976, The star ιOri, The star θ2Ori, The star θ1Ori
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M42 - The Great Orion Nebula - in NbLRGB, 





    
        

            Cfosterstars

M42 - The Great Orion Nebula - in NbLRGB

Technical card

Resolution: 9031x6746

Dates:Nov. 16, 2018Dec. 2, 2018Dec. 4, 2018Dec. 17, 2018Dec. 20, 2018Dec. 27, 2018Jan. 1, 2019Jan. 4, 2019Jan. 5, 2019Jan. 10, 2019Jan. 12, 2019

Frames:
Astrodon 36mm Ha 5nm: 60x10" (gain: 200.00) -15C bin 1x1
Astrodon 36mm Ha 5nm: 60x300" (gain: 200.00) -15C bin 1x1
Astrodon 36mm Ha 5nm: 40x45" (gain: 200.00) -15C bin 1x1
Astrodon 36mm O3 5nm: 60x45" (gain: 200.00) -15C bin 1x1
Astrodon 36mm O3 5nm: 60x300" (gain: 76.00) -15C bin 1x1
Astrodon 36mm SII 5nm: 60x300" (gain: 200.00) -15C bin 1x1
Astrodon Blue Tru-Balance E-series gen 2: 60x10" (gain: 76.00) -15C bin 1x1
Astrodon Blue Tru-Balance E-series gen 2: 159x90" (gain: 76.00) -15C bin 1x1
Astrodon Green Tru-Balance E-series gen 2: 60x10" (gain: 76.00) -15C bin 1x1
Astrodon Green Tru-Balance E-series gen 2: 170x90" (gain: 76.00) -15C bin 1x1
Astrodon Luminance Tru-Balance E-series gen 2: 60x10" (gain: 76.00) -15C bin 1x1
Astrodon Luminance Tru-Balance E-series gen 2: 60x30" (gain: 76.00) -15C bin 1x1
Astrodon Luminance Tru-Balance E-series gen 2: 120x300" (gain: 76.00) -15C bin 1x1
Astrodon Red Tru-Balance E-series gen 2: 60x10" (gain: 76.00) -15C bin 1x1
Astrodon Red Tru-Balance E-series gen 2: 168x90" (gain: 76.00) -15C bin 1x1

Integration: 40.0 hours

Darks: ~40

Flats: ~40

Flat darks: ~40

Avg. Moon age: 17.59 days

Avg. Moon phase: 35.96%

Bortle Dark-Sky Scale: 5.00

Astrometry.net job: 2501401

Locations: Backyard, Austin, TX, United States

Data source: Backyard

Description

This is half of my winter project of the Orion Nebula and Running Man nebula. This is the first panel and is processed with LRGB and Ha, OIII and SII data. I had several problems in processing. First was the star color when stretched for the RGB data. The ArcsinhStretch seems to always generate color artifacts with the stars. I also had a lot of issues blending the NB data into the RGB. I was not successful with the NBRGBCombination script so I used a blend of the RGB and a false color image from the NB filters using the blend script. I still need to figure out how to fix the star color. The fringe halos are not a consistent color. The microlensing artifacts around the bright stars is inherent with the ASI1600MM-Pro sensor.

Comments

Author

cfosterstars
Cfosterstars
License: None (All rights reserved)
3170
Like

Revisions

  • M42 - The Great Orion Nebula - in NbLRGB, 





    
        

            Cfosterstars
    Original
  • Final
    M42 - The Great Orion Nebula - in NbLRGB, 





    
        

            Cfosterstars
    B

B

I spent a huge amount of time in reprocessing this data. I was unhappy with the stars in particular. They had artifacts that I was able to nail down as coming from the process of non-linear stretching both the RGB and LUM data. With some hints from Adam Block, I stretched the images differently. ArcSinhStretch, when used from the beginning for the initial stretch, will result in ugly color artifacts. I stretched the RGB data first using the STF function to find a nice medium stretch - not the AutoSTF stretch that often will wash out the color. I used this as the initial stretch to about 80% of the total stretch. Then I went back to ArcSinhStretch to do most of the remaining stretch. This really saves the color saturation of the data while not causing star artifacts. Then a final tweak stretch with the histogram transformation for the blackpoint. The key was to not over stretch the data so that LRGBCombination will have headroom when the lum data is added. I also induced artifacts in the stars from the LUM stretching. Again I used the STF tool and histogram transformation for the initial stretch - this time about 50% of the stretch. I then used maskstretch for the rest of the stretch. This really preserves the detail in the bright core region while getting most of the background nebulosity visible. I then used a mask to protect the core and used exponential transformation to stretch to dimmer nebulosity. These changes to the stretching fixed my star artifacts. I also used a single reference for aligning all my subframes instead of doing it by filter so I had only one instance of interpolation in the data. I also did deconvolution of each of the filter channel master light frames independently instead of only on the combined lum. I used a different method of blending in the narrowband data to include all the narrowband filters. Needless to say that this took many days to complete but I am very happy with the improvements. I also did not over do the color saturations so it Ha is less pink. The end result has NO noise reduction at all. I hope you like it. C&C welcome.

Histogram

M42 - The Great Orion Nebula - in NbLRGB, 





    
        

            Cfosterstars