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Contains:  NGC 7023
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NGC 7023 - The Iris nebula in Cepheus, 





    
        

            Daniel.P
NGC 7023 - The Iris nebula in Cepheus

NGC 7023 - The Iris nebula in Cepheus

Technical card

Resolution: 3040x2024

Dates:July 27, 2016Aug. 1, 2016

Frames: 24x900" -15C bin 1x1

Integration: 6.0 hours

Darks: ~7

Flats: ~5

Bias: ~50

Avg. Moon age: 25.42 days

Avg. Moon phase: 23.01%

Mean SQM: 21.10

Mean FWHM: 2.10

Temperature: 18.00

Astrometry.net job: 1234169

RA center: 315.422 degrees

DEC center: 68.167 degrees

Pixel scale: 0.761 arcsec/pixel

Orientation: -3.462 degrees

Field radius: 0.386 degrees

Locations: Duc, Prayssas, Lot et Garonne, France

Description

The second photo of this summer ... the color of the stars ned to be improved.

FWHM measured in PI : 2.1 arcsec (Moffat 4) : the seeing was quite good on average, ranging between 2.4 to 1.6 arcsec on sub exposures

I was not able to apply Background Equalization process on this image due to the nebula covering the whole image. If someone has experience of how to use DBE process in PI in this situation, I would like very much to share experience.

I am doing some processes on the non linear image now : TGV denoise with linear mask, HRD, color sat, Multiscale denoising. The main advantage is that it is easier to tune masking and use linear mask in some processes.

I also denoise under the following scheme : TGV to remove small scale noise and fine tune larger scale noise in low signal area using Multi Scale denoising processes.

Pre-processing done in Pixinsight :
- overscan area offset correction
- bias correction
- dark correction using 7 x 1800 s darks
- flat correction
- hot pixel correction
- debayer
- registration
- stack
Processing done in Pixinsight :
- backgroung color neutralisation
- color calibration using nebula
- non linear image creation
- HDR compression, scale 8, overdrive 0.4, median transform,
- TGV denoise : to remove small scale noise, using a linear mask
- Median Multi Scale noise reduction masked, to remove remaining larger scale noise (scale 8)
- color saturation boost masked
- green neutral
- final color adjust
Final image :
- jpeg calibration done in Mac Photo (levels adjust and further saturation boost and color balance)

Comments

Author

Daniel.P
Daniel.P
License: None (All rights reserved)
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NGC 7023 - The Iris nebula in Cepheus, 





    
        

            Daniel.P