The Spectrum and Variability of Hercules X-1 Observed by OSO-7

We report observations of Her X-1 (HZ Her) with the UCSD 080-7 X-ray telescope 1971 December 8-11 and 19'72 May 29-June 1. The time variable phenomena we see are: (1) the 1.7-day eclipse; (2) the X-ray source is seen more than one day before predicted (1972 May 31) by the 35.7-day ON-OFF cycle; (3) evidence for precursor "dips" in intensity relative to the eclipse (1.7- day period). We aiso show that the number spectrum (photons cm-2 -5 keV-1) steepens by 2.5 in the spectral index (from 1) above 25 keV.