RX J0640-24 rapid fading We started the second night's observation on RX J0640-24 at 14:45 (UT). Although our CCD image on display is hazy, the current magnitude seems to be 14mag, which indicates RX J0640-24 shows rapid fading. It is possible that we see a precursor of superoutburst or an outburst of IPs. The follow-up observation is very encouraged to clarify the nature of this outburst. Regards, Makoto Uemura and Taichi Kato