The EXOSAT observations of SS Cygni

A series of nine observations of SS Cygni made using EXOSAT between 1983 November and 1984 September are presented. Distinct soft and hard X-ray emitting components were spectrally resolved by the LE and ME instruments respectively. In quiescence the source shows hard X-ray emission with a 2-10 keV luminosity of 1.2 × 10 33 (d/200 pc) 2 erg/s. The hard X-ray emission is suppressed in outburst but shows no significant increase in photoelectric absorption. The soft X-ray emission approximately follows the optical behaviour, but the outburst is delayed by 0.5-1.1 d from the optical