Solar energetic particle event onset, observed over 12 h on Nov. 4, 2001 by GOES and SOHO. The top panel shows the GOES/SXT low-energy X-ray flux. The second panel from top shows a spectrogram of energetic electrons in the 0.25–10 MeV range observed by SOHO/COSTEP-EPHIN. Below that is displayed a 4–50 MeV proton spectrograms observed by EPHIN, and at the bottom the SEPEM energy channels of GOES-8/SEM displayed as a spectrogram. Only energy channels with full overlap between GOES 8/SEM and EPHIN are shown.