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Contains:  Crescent nebula, NGC 6888
Getting plate-solving status, please wait...
NGC 6888 HOO_RGB - Crescent Nebula in Cygnus, 





    
        

            Daniel.P

NGC 6888 HOO_RGB - Crescent Nebula in Cygnus

Technical card

Resolution: 4486x3390

Dates:May 10, 2018Aug. 10, 2018Aug. 15, 2018

Frames:
AstroDon 5nm Ha filter: 3x300" (gain: 139.00) -15C bin 1x1
AstroDon 5nm Ha filter: 6x600" (gain: 139.00) -15C bin 1x1
AstroDon 5nm OIII filter: 3x300" (gain: 139.00) -15C bin 1x1
AstroDon 5nm OIII filter: 5x600" (gain: 139.00) -18C bin 1x1
ZWO new B: 6x120" (gain: 139.00) -18C bin 1x1
ZWO new G: 6x120" (gain: 139.00) -18C bin 1x1
ZWO new R: 6x120" (gain: 139.00) -18C bin 1x1

Integration: 2.9 hours

Avg. Moon age: 19.14 days

Avg. Moon phase: 16.80%

Astrometry.net job: 2444705

Locations: Duc, Prayssas, Lot et Garonne, France

Data source: Backyard

Description

This image is the combination of the 30 min exposure of the May 10th earlier this year with the summer data of this nebula.
The seeing was not so good on these exposures (R: 3", B: 3.5", Ha: 2.7", O3: 3.5")

I have included the :
- H alpha version
- the RGB data
- the final version is a test to further match the star color with the RGB color without artifact. I have used a Max functionin PixelMath, something like :
Max(RGBHOO , RGBHOO * (1-starmask) + RGB * starmask)

The max function is efficient to avoid dark ring around star.

The processing was done in PI as follow (version original):
For each R ,G ,V, Ha, OIII & SII channels :
- Flat Field Dark Substraction
- Flat Field Integration
- Images Calibration (Dark Substraction for RGBSHO and FF correction only for RGB (no need for SHO ...))
- Cosmetic Correction
- Image Registration
- Image Integration
- Noise Reduction (Demure) with 1 as variance

Using each integrated channel :
- Created RGB color image using channel combination
- Color balance on stars
- Created RGBSHO image using NBLRGB combination tool
- Nonlinear Image Creation using NBRGB values
- Color balance on all image
- Perform SCNR (neutral 100%)
- Color saturation with boost in blue and mask to protect dark area.
- Final manual color balance to boost blue

Final image adjustments performed in Iphoto on Imac (levels adjustments, +15% color sat, +10% definition, and deflip & crop)

Comments

Author

Daniel.P
Daniel.P
License: None (All rights reserved)
1730
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Revisions

  • NGC 6888 HOO_RGB - Crescent Nebula in Cygnus, 





    
        

            Daniel.P
    Original
  • NGC 6888 HOO_RGB - Crescent Nebula in Cygnus, 





    
        

            Daniel.P
    B
  • NGC 6888 HOO_RGB - Crescent Nebula in Cygnus, 





    
        

            Daniel.P
    C
  • NGC 6888 HOO_RGB - Crescent Nebula in Cygnus, 





    
        

            Daniel.P
    E
  • Final
    NGC 6888 HOO_RGB - Crescent Nebula in Cygnus, 





    
        

            Daniel.P
    G

B

H alpha

C

RGB

E

Star color adjusted in HOO-RGB

G

Same as E but with a darker sky background

Histogram

NGC 6888 HOO_RGB - Crescent Nebula in Cygnus, 





    
        

            Daniel.P

In these public groups

ZWO ASI1600MM/QHY163M