Historically a Windows-only tool, DeepSkyStacker has recently expanded its reach:
Deep Sky Stacker is designed to work with images taken using a digital camera or a CCD (Charge-Coupled Device) camera, and can be used with a variety of telescopes and mounts. The software is capable of handling large images and can produce high-quality results with minimal user input. deep sky stacker download install
Installing the software is only half the battle. You must now configure it to work with your specific camera. Historically a Windows-only tool
DSS 5.x uses an older build of LibRAW that doesn't support new Canon CR3 compression. Fix: deep sky stacker download install