Gum 84 (Sh2-54) region and the Eagle Nebula (M16) in the constellation Serpens, together with the Omega Nebula (M17) in the constellation Sagittarius, line up in the center part of the Milky Way galaxy. I am always fascinated by the rich features of this area and the surroundings.
The attempt was done in my city backyard. I tried a couple of color palettes and decided that a modified SHO palette expose the most details from narrowband channels. It's kind of a "dark theme" style. The whole image is made of 3 panels shot at 318mm focal lens with the ASI1600mm-Pro's 4/3 sensor. I might try to make a "natural color palette" version later. Hmm...
But, I love the starless version so much. Much much more dramatic.
I am glad that 9 narrowband masters and 9 RGB masters all come together successfully. The mosaic integration function of Astro Pixel Processor really delivers.
It's a quite long project over 40 nights (Gosh... 🤣 !). Learned quite a bit about the filters and the trade-off of the fast optics (well, fast optics really have serious performance impact by the sky glows from the heavy light pollution. I truly hope it could deliver at the dark sites!)
For the first time, I refuse to key in the acquisition details (there are just too many entries!). Let me summarize here.
Dates
2020/05/29 ~ 2020/08/09
Data Details
H-Alpha - 364 x 300s, Gain 139, -10C
Surfur-II - 360 x 300s, Gain 139, -10C
Oxygen-III - 373 x 300s, Gain 139, -10C
Red - 66 x 60s, Gain 0, -10C
Blue - 66 x 60s, Gain 0, -10C
Green - 66 x 60s, Gain 0, -10C
A little bit about the mosaic integration with Astro Pixel Processor. The light pollution is so bad that I have to integrate each channel for each pane separately, flat each of the masters, then perform mosaic registration again.
Pre-processing of Narrowband Masters
– Calibration / Integration, Astro Pixel Processor
- Dynamic Background Extraction for each channel master on each target, PixInsight
– Mosaic Integration, Astro Pixel Processor
- Dynamic Background Extraction for each channel's mosaic master, PixInsight
– Deconvolution, PixInsight (H-Alpha)
– MultiscaleLinearTransform (Denoise), PixInsight
- Range Selection, PixInsight
- PixelMath, PixInsight
– ScreenTransferFunction / HistogramTransformation, PixInsight.
Pre-processing of RGB Masters
– Calibration / Integration, Astro Pixel Processor
- Dynamic Background Extraction for each channel master on each target, PixInsight
– Mosaic Integration, Astro Pixel Processor
- Dynamic Background Extraction for each channel's mosaic master, PixInsight
– MorphologicalTransformation, PixInsight
– ScreenTransferFunction / HistogramTransformation, PixInsight.
RGB Combination
– LRGBCombination, PixInsight
– MorphologicalTransformation, PixInsight
– ScreenTransferFunction / HistogramTransformation, PixInsight.
Narrowband Combination
- SHO-AIP script, PixInsight
- ColorMask script, PixInsight
- CurveTransformation
– PixelMath, PixInsight
– ScreenTransferFunction / HistogramTransformation, PixInsight.
Narrband & RGB Combination
– PixelMath, PixInsight
- Detail adjustments, Adobe Photoshop CS
– Final Export, Photoshop
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