could you explain what a non-linear image is in the context of processing astrophotos ? I process my DSLR images with siril in always the same manner. Mostly it works fine, but for some images, it completely refused to work with a split second of time. I dont think this is because the image is non-linear. That doesnt make sense. It also doesnt even attempt to find stars, or states that it found only a single star when there are hundreds in the image.