Polydeuces was discovered by the Cassini Imaging Team on October 24, 2004, in images taken on October 21, 2004, and given the temporary designation S/2004 S 5.
== Odkritje in imenovanje ==Luno Heleno sta odkrila Pierre Laques in Jean Lecacheux v letu 1980 na Observatoriju Pic du Midi v Pirenejih.