Hercules A, or 3C 348, is a bright astronomical radio source galaxy in the constellation Hercules. It is an elliptical galaxy, and the origin of one of the largest known astronomical radio sources, emanating 459,820 light years on either side of its point of origin, making the feature nearly a million light years across. Hercules A was first catalogued by astronomers at the University of Cambridge in April 1961 in a paper published to The Observatory.