Stjernsundet is a strait in Finnmark, Norway. It separates the island of Stjernøya from the mainland. Stjernsundet leads from the outer part of Altafjorden, and opens up westwards into Lopphavet.[1] [2] During the World War II Operation Source, a number of British X-crafts found their way from Lopphavet through Stjernsundet and succeeded in attacking and damaging the German battleship Tirpitz in Kåfjorden, an inner branch of Altafjorden.