Siril is a powerful open-source software package designed for the preprocessing and post-processing of astronomical images. It is particularly well-suited for astrophotography enthusiasts and professional astronomers alike. Siril provides advanced tools for tasks such as image stacking, calibration, registration, and enhancement, enabling users to produce high-quality images of celestial objects. The version discussed here is the development branch 1.4, which, while not officially released, is available for testing and includes the latest features and improvements.