The type II supernova 1979c in M100 and the distance to the Virgo cluster

Intensity calibrated optical spectrophotometric observations of supernova 1979c in M100 were obtained between April 22, 1979 and November 24, 1979. The time development of the spectrum appears typical for type II events, except perhaps that the H-alpha feature never appears in P Cygni form. Synthetic spectra computed using a blackbody photosphere and a pure scattering expanding atmosphere successfully model the continua and P Cygni profiles of the supernova spectra up to May 28. The distance to the supernova is determined using the Baade method and found to be 23 + or - 3 (rms) Mpc, corresponding to a Hubble parameter of about 60 km/s-Mpc.