Siril calibration errors: number of channels is different

Software Siril
1

I’m just getting started with astrophotography and Siril, and I am attempting to process some raw photos I took of the night sky. I followed a couple YouTube tutorials and used the OSC_Preprocessing script, but I am getting stuck on image calibration. I took biases, darks, and flats, but if I try to calibrate using any of those, I get errors like “NOT USING FLAT: number of channels is different” and so on. I don’t know what this means or what I am doing wrong, and I can’t find much information on this. These stacks were created with the OSC_Preprocessing script.

So what am I doing wrong in my process? Here are a couple screenshots in case this is helpful. (There is a ton of light pollution…the bright star bottom-center is Altair which was the only star visible to the naked eye, so I’m impressed with what’s going on here).

siril
siril1871×1022 249 KB

siril2
siril21871×1022 166 KB

For additional info, I am using Siril-1.2.3 AppImage on Linux Mint 21.3. Photos were taken with a Canon EOS R50 in RAW mode which created .CR3 files.

2

That means your flat are already debayerd. And this is a mistake. You should have a look to the documentation. Especially here:
https://siril.readthedocs.io/en/stable/preprocessing/calibration.html#troubleshooting-calibration

3

I followed a different guide to manually preprocess everything. It worked with image calibration, but the result is the same. So I think the script must have already done the calibration, which wasn’t clear to me before. And I think most of the color gradient must be light pollution and airglow rather than sensor artifacts that didn’t get calibrated away.

I clearly have a lot to learn.

4

it looks like you are using the GUI, not the scripts, your images are already in 3 colours, which is not supposed to happen before calibrating them.
And it looks more like a cloud pass than light pollution