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The Lagoon Nebula (M8) imaged in SHO-RGB

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    Vostok 1

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Posted 29 June 2020 - 09:07 PM



The Lagoon Nebula (M8) imaged in SHO-RGB by Andrew Klinger, on Flickr


In this rendition of The Lagoon Nebula, I blended natural color stars into the false-color image of the nebula. The warmer tones represent where Sulfur and Hydrogen lie in the nebula, while the blues represent the Oxygen emissions.


OTA: William Optics GT81 w/0.8x reducer (382mm fl at f/4.7)
74mm aperture stop-down ring (brings scope to f/5.2)
Mount: Orion Sirius EQ-G (HEQ-5)
Guidescope: Orion 50mm guidescope
Guiding camera: Orion StarShoot Autoguider
Imaging camera: ZWO ASI1600MM-Cool


DeepSkyDad Autofocuser AF1
QHYCCD PoleMaster



Flower Mound, TX for Ha(Bortle 7) - 2018 data
Atoka, OK for RGB(Bortle 3) - 2018 data
Ft. Griffin State Historic Site, TX for OIII and SII(Bortle 2) - 2020 data
Dates: 6/11/18, 7/31/18, 8/1/18, 6/24/20
Gain: 200 Offset: 50 for Ha
Gain: 76 Offset: 15 for RGB
Camera temp: -10C
SII: 25x300" Astrodon 3nm
Ha: 74x300" Astrodon 5nm
OIII: 26x300" Astrodon 3nm
R: 33x180"
G: 27x180"
B: 30x180"
Total integration time: 14hr 55min
64x darks per calibration (master from library)
30x flats per calibration
200x bias per calibration (master from library)


Batch PreProcessing script to generate calibrated images


Luminance Processing:
Duplicated the master Ha to use as the luminance
ArcsinhStretch and HistogramTransformation to bring to non-linear
HDRMT on the core area
Created a duplicate starless version using StarNet++
Combined the starless version with the image using PixelMath expression "F=0.4; (1-(1-$T)*(1-s)*F)+($T*~F)". (s=starless photo)
MultiscaleLinearTransform for sharpening
MorphologicalTransformation using a star mask to completely remove the stars


Preparing separate Sii, Ha, and Oiii linear masters for tonemapping (applied to each master individually):
TGV noise reduction (via Jon Rista's method)
ArcsinhStretch and HistogramTransformation to bring to non-linear
HDRMT on the core area (Ha and OIII only)
Removed stars via StarNet++


Preparing RGB image:
ChannelCombination to create the color image
SCNR Green
ArcsinhStretch and HistogramTransformation to bring to non-linear
SCNR Green
CurvesTransformation for saturation
SCNR Green (I'm really making sure no stars are green since that is all I'm using this for)
StarNet++ to remove stars and create an RGB star mask


Combined prepared Sii, Ha, and Oiii masters with ChannelCombination:
R: Sii
G: Ha
B: Oiii


Tonemap Processing:
HistogramTransformations to balance colors
CurvesTransformations using ColorMasks
Invert>SCNR Green>Invert to remove magenta in core area
CurvesTransformations for saturation adjustments


Combined Tonemap with Luminance using LRGBCombination


Added in RGB stars using the RGB star mask and PixelMath to add the RGB star-only image to the tonemap


MorphologicalTransformation to slightly reduce star sizes
CurvesTransformation to saturate stars
UnsharpMask to slightly sharpen stars
A few cosmetic adjustments to fix introduced RGB artifacts
Resampled to 80% for web posting

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#2 APshooter



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Posted 29 June 2020 - 09:09 PM

Wow, that's nice.

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#3 Simcal


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Posted 29 June 2020 - 09:18 PM

wow, and excellent processing details, ..thank you.

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#4 sunnyday



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Posted 29 June 2020 - 09:23 PM

superb photo with details and colors absolutely beautiful.
well done and thank you.

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#5 brian1052


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Posted 29 June 2020 - 09:51 PM


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#6 futuneral



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Posted 29 June 2020 - 10:19 PM

Amazing rendition and thank you for the processing details - will definitely try some of those approaches.

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#7 Jim R

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Posted 29 June 2020 - 10:40 PM

Yet another poster for me to admire their skills.

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#8 chrysalis



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Posted 30 June 2020 - 09:26 AM

Beautiful and psychedelic :bow: !! 

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#9 TareqPhoto


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Posted 30 June 2020 - 10:16 AM

Amazing nice image!

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#10 Fernando134



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Posted 30 June 2020 - 01:13 PM

Great image!!!

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