OBSERVATIONS OF CEN X-3 WITH GRANAT ART-P

Two sessions of Cen X-3 observations, covering the 0.54-0.90 orbital p hases, were performed with GRANAT/ART-P on Feb 10 and Aug 19, 1990. Th e measured pulse periods were 4.821536+/-0.000016 and 4.820909+/-0.000 014 s respectively. Several outbursts of the source emission (by simil ar to 2 times in intensity on a time scale of hundreds seconds) which were accompanied strong changes in the spectral hardness were observed during the observations. The spectral analysis has shown also that th e spectral hardness and low energy absorption of the source emission i s correlated with the orbital phase.