There are two types of L-RGB processing with CFALD.
1) Non-calibrated, giving supererior SNR, but possible vignetting and dust spots (great for masking luminance over galaxies and small nebula).
2) Calibrated CFALD, used as a base luminance with RGB over layered over the top as colour, and a star overlay.
Here we have tutorials for both with example images to practise processing.
We stack RGB as normal using DSSQ, then run CFALD on the uncalibrated, non-debayered lights found in process using siril. Run CFALD on them BEFORE calibrating to pp_lights, or move them out wile running CFALD.py so it doesn't make luminances of ALL of the files in process.
Then we calibrate and stack the lights as normal. Then stack the CFALD separately, and use this as an overlay luminance, over the RGB stack, and mask AROUND the areas of interest, and stretch this luminance. If we didn't mask, the lack of flats would show vignetting and spots etc.
So, to do this just run the cfald script on the Lightsxxxx.fits in the process folder. Then stack and process the CFALD as a luminance overlay.
Here we need to generate calibrated pp_lights, but force Siril to NOT DEBAYER it. This creates an extra step and uses a lot more drive space. The calibration causes some photosite decoherence, so we loose a lot of SNR, but gain a calibrated luminance that we can use over the whole image without masking it.
So, to do this run the scripts below.
Use the luminance as the bottom layer, then remove the stars on the RGB, blur it slightly and use that as a HSL Colour layer over it. Then we can stretch and modify the CFALD below to avoid stretching the chroma.
Then ADD the stars back with the RGB stack, masking OUT the background, so just the stars remain.
Siril Script for pp_Lights...
# === Convert Bias Frames ===
cd biases
convert bias -out=../process
cd ../process
# === Create master bias ===
stack bias rej 3 3 -nonorm -out=../masters/bias_stacked
cd ..
# === Convert Flat Frames ===
cd flats
convert flat -out=../process
cd ../process
# === Calibrate flats using master bias ===
calibrate flat -bias=../masters/bias_stacked
# === Stack Flat Frames to create master flat ===
stack pp_flat rej 3 3 -norm=mul -out=../masters/pp_flat_stacked
cd ..
# === Convert Light Frames ===
cd lights
convert light -out=../process
cd ../process
# === Calibrate Light Frames (NO DARK, KEEP CFA, NO DEBAYER) ===
calibrate light -flat=../masters/pp_flat_stacked -bias=../masters/bias_stacked -cfa
# === DONE — Your calibrated CFA frames are pp_light_*.fit ===
cd ..
close
We then run CFALD on these pp_lights in the process folder. See below.
Delete all the other flats and biases frames out of there. They are NOT NEEDED now and are taking up space (the masters are in the masters folder).
Then we need to debayer these pp_Lights fames to pp_pp_lights, then register and stack these.
# === Calibrate Debayer Light Frames
cd process
#calibrate pp_light -equalize_cfa -debayer
register pp_pp_light
stack r_pp_pp_light rej 3 3 -norm=addscale -output_norm -rgb_equal -32b -out=RGBStack
cd ..
So copy these scripts, save the first as "calibrate.ssf"
And the second as "Stack.ssf".
or whatever you wish.
CFALD PYTHON Script
https://drive.google.com/file/d/1VQnYvmPYdXvUIYDaNceBEIaDx3OtRQTT/view?usp=sharing
CFA-RGB-BIN Python Script
https://drive.google.com/file/d/19mdb0oX5NNcf3lyGSOWYyVtRxsGcLvyb/view?usp=sharing