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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
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NGC 6888 HOO_RGB - Crescent Nebula in Cygnus

Imaging telescopes or lenses: TS Optics APO130f6

Imaging cameras: ZWO ASI1600MM-Cool

Mounts: Ioptron CEM 120 EC2

Guiding telescopes or lenses: TS Optics APO130f6

Guiding cameras: Starlight Express Lodestar X2 Autoguider

Focal reducers: TS-Optics TSFlat 2

Software: Sequence Generator Pro  ·  PixInsight  ·  PHD Guiding 2.5.0

Filters: ZWO new B  ·  ZWO new G  ·  ZWO new R  ·  AstroDon 5nm Ha filter  ·  AstroDon 5nm SII filter  ·  AstroDon 5nm OIII filter

Accessory: ZWO EFW 31mm 8 positions  ·  Starlight Xpress AO Unit  ·  QHYCCD PoleMaster  ·  Innovations Foresight ONAG  ·  USB_Focus V3 Usb Focus  ·  USB Stepper Motor Heavy Load


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%


Basic astrometry details

Astrometry.net job: 2443226

RA center: 20h 12' 23"

DEC center: +38° 18' 54"

Pixel scale: 0.913 arcsec/pixel

Orientation: 0.174 degrees

Field radius: 0.713 degrees


Resolution: 4486x3390

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)
1940
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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

Description: H alpha

C

Description: RGB

E

Description: Star color adjusted in HOO-RGB

G

Description: Same as E but with a darker sky background

Sky plot

Sky plot

Histogram

NGC 6888 HOO_RGB - Crescent Nebula in Cygnus, 



    
        

            Daniel.P

In these public groups

ZWO ASI1600MM/QHY163M