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2013: NGC 6888; The Crescent Nebula in HaHa(HaR)GB
Image details
Date: June  26, 27, and 28, 2011 (RGB), and June 6,7, and 8, 2013 (Ha)
Exposure: 3 hours 45 min (45x 5 min), ISO 1600, 16 Darks, 20 Bias, and 20 Flats (RGB), and 6 hours (18x 20 min), ISO800, 12 Darks, 30 Flat darks, and 30 Flats (Ha)

Telescope: 8" Skywatcher Newton
@F/5 with MPCC and Baader 7 nm Ha-filter 
Mount: NEQ6-pro, controled by EQmod/CdC, guided by  QHY5/9x50 Finder Guider/PHD
Camera: Peltier-cooled Canon 350Da 
Location: Emmen, The Netherlands

High resolution: (2,63 Mb)
DSLR-LLRGB post-processing luminance work flow  according to Scott Rosen's video tutorial, and Starizona's Ha(HaR)GB method:


Original 32-bit floating point RGB image in Photoshop CS3:
 -Black out Blue and Green color channels
-Convert to 16-bits greyscale
 -Convert back to RGB [RGB reconvertion is only done for easy of interpretation of PS histgram and tools]
 -Star repair
 -Levels correction for background black-, and white points
 -Curves, selective on weak Ha clouds in the background and Ha whisps in NGC6888, with anchored background and highlights, 2x normal curve
 -High pass filtering on the details in NGC6888 (40px & 8px; Don Goldman method)
 -Carboni's v1.6 Deep Space Noise Reduction [Removes noise from background, not DSO]
 -GradientXterminator (med/low and fine/med)
 -Levels (blackpoint restoration)

 -Curvess (slight anchored brightning curve)

RGB data processed using Noel Carboni's Astronomy Tools v1.6
 -16 bit Tiff file from DSS 3.3.2 opened in Nebulosity 2.5 for auto color balance
 -Photoshop CS3; 
Gradient removal
Photoshop CS3; Levels and Curves
 -Photoshop CS3; Hasta La Vista Green
Photoshop CS3; Color range increase saturation
 -Photoshop CS3 Carboni Astronomy Tools v1.6; Deep Space Noise Reduction)
 -Photoshop CS3; GradientXterminator (med/low and fine/med)

HaRGB combine in Photoshop CS3
 -Expand RGB image to indentical image size as Ha image (due to different crops of stacked edges)
 -Register and align in DSS 3.3.2
 -Extract R-channel from RGB image and paste on top of Ha image, normal blending, 30% opacity, HaR30
 -Paste HaR back to R-channel in RGB image to form (HaR30)GB image
 -Stretch R-channel with levels to increase starsizes and color to match original RGB, keeping an eye out on overal starcolor in theimage to keep as close to original RGB image
 -Insert Ha in luminosity blend at 30% opacity
 -Increase saturation by Adam Block method; 2 times
 -Hasta La Vista Green; medium
 -Insert Ha in luminosity blend at 60% opacity
 -Levels (blackpoint restoration)

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