This section takes you through the different steps of pre-processing your images, from import into Siril to obtaining a stacked image.

The right pane contains the tabs that are useful during preprocessing. They have been designed to be used from left to right throughout the process, with some exception for the creation of masters. These tabs are also accessible via the keys F1 to F7.

Pre-processing is the step that starts with the conversion to the stacking of the images. The goal is to remove all unwanted signals and to reduce the noise present on all the subs.

preprocessing schema

Image 1 shows the result of the conversion of a raw digital camera image. You can see visible dust, similar to dark spots. Image 2, after calibration of the images by the master darks, bias and flats shows the complete removal of these spots and a cleaner signal. Image 3 is the same after demosaicing, showing color and a very large green cast due to the higher sensitivity of the green photosites on the sensors. Finally, image 4 is the stacking output, with channel balancing.