RegiStax V3 software is a popular image processing software used for astrophotography. It allows users to stack and align multiple images of celestial objects to produce a clearer, more detailed final image. The software includes a variety of processing tools, such as wavelet sharpening and noise reduction, to enhance the final image. Additionally, RegiStax V3 supports a wide range of image file formats and provides options for advanced users to customize their processing settings.