The Great Solar Radio Burst of may 23, 1967

On May 23, 1967, a solar radio burst was observed that was one of the largest ever recorded; it was associated with an Importance 2B flare. Using high-accuracy flux-density measurements at five fre- quencies ranging from 606 to 8800 MHz, its flux-density spectrum was compared with spectra of other flares observed in white light. It was found that along with most of the other white-light flares it dis- played the U-type flux-density spectrum, i.e, high flux density in the meter and centimeter range and lower flux density in the decimeter range. The flare produced a PCA