The uploads are much appreciated!
It was very helpful; on closer inspection, the problem I'm seeing has nothing to do with APP or channel alignment. Rather, is the pretty severe chromatic aberration of the Samyang. Combined with some star deformity (see top/corners of the image), it can make it hard for stackers (and StarTools) to latch on to stars and detail.
The other thing, the yellow-ish color cast, which threw me off is visible the single frame too. It is likely due to not using an IR/UV filter (correct?), which sees the green channel response increase past the visual spectrum (
see here).
If the chromatic aberration bothers you, acquiring narrowband is always an option too.
Honestly, it's not an easy object in the visual spectrum, and the chromatic aberration combined with this being a wide field makes it a lot trickier to process.
I ended up with something like this;
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- IC1396-NoSt.jpg (1.37 MiB) Viewed 5834 times
Processed in 1.7.412 alpha as follows;
Imported, using second option.
---
Type of Data: Linear and was Bayered, but not whitebalanced
--- Auto Develop
To see what we got.
--- Bin
To improve signal, use oversampling.
Parameter [Scale] set to [(scale/noise reduction 70.71%)/(200.00%)/(+1.00 bits)]
Image size is 1952 x 1959
--- Crop
Get rid of stacking artifacts.
Parameter [X1] set to [8 pixels]
Parameter [Y1] set to [12 pixels]
Parameter [X2] set to [1931 pixels (-21)]
Parameter [Y2] set to [1947 pixels (-12)]
Image size is 1923 x 1935
--- Wipe
Default.
--- Auto Develop
Default.
--- Wavelet Sharpen
Parameter [Structure Size] set to [Large]
--- SNR-aware Wavelet Sharpening
Auto-generate mask.
Parameter [Mask Fuzz] set to [10 pixels]
Parameter [Amount] set to [500 %]
--- Deconvolution
Auto-generate mask, though had to manually shrink it twice to avoid some artefacts .
Parameter [Primary Radius] set to [1.1 pixels]
--- Life
Default (reset mask to select all pixels)
Push back busy star field and re-focus attention on large scale nebulosity.
--- Color
Color constancy fails miserably here due to chromatic aberration.
The Legacy preset (Parameter [Style] set to [Artistic, Not Detail Aware]) mimics how less-sophisticated software such as PI, PS APP, etc. desaturates highlights as you process the image.
Parameter [Cap Green] set to [100 %] to remove any spurious green; chromatic aberration (incorrect focusing of different wavelenghts) tends to focus only green correctly, but not other channels, causing, for example star cores, to appear green, with blue and red energy scatterd across neighboring pixels.
Parameter [Highlight Repair] set to [4 pixels] to further repair star colors in over-exposing star cores.
It's just very challenging getting star colors to look ok, but at least we end up with a fairly reasonable representation of all black body radiation curve temperatures;
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- Selection_170.png (108.36 KiB) Viewed 5834 times
--- Wavelet De-Noise (siwtch off Tracking)
Parameter [Grain Size] set to [3.5 pixels]
--- Wavelet De-Noise
Default.
Hope this helps at all!
EDIT: You can also keep it simple, and not try to enhance the structures;
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- IC1396-NoSt-2.jpg (508.23 KiB) Viewed 5833 times