Supernova after four centuries

The discovery is described of the supernova of 24 Feb 1987. Prior to astronomical observation, neutrino pulses were recorded. Briefly summarized is the existing knowledge of supernovas and the properties of the newly discovered one. It obviously is a new, still unknown type of supernova. Its progenitor was a blue giant of the B3 spectral type. In neutrino detection, their non-zero rest mass was confirmed and determined to be 2.67x10-35 kg. (M.D.). 3 figs., 1 tab