Einstein and EXOSAT observations of geminga (1E0630+178). A summary of the short - and medium - term variability data

The X-ray source 1E 0630 + 178 was discovered by Bignami et al. (1983) during an X-ray survey. The survey was conducted with the aid of the Einstein Observatory. The involved field was also observed with the Exosat satellite in September 1983, when both Low Energy telescopes were still operating. The Einstein and Exosat data bases were utilized in an analysis. Evidence for periodicity was found in both the Einstein and Exosat data. The Exosat CMA 1 and CMA 2 fields are shown together with the Einstein IPC and HRI data. Attention is given to a saturation curve of the Geminga source in the IPC 10371 observation, the secular variation of the 59 sec periodicity of Geminga, and 'a posteriori' period scans for the IPC+HRI data set and the CMA1+CMA2 data set.