RXTE PCA Detects the Millisecond Pulsar SAX J1808.4-3658 in Outburst

Regular RXTE PCA monitoring observations on 2008-09-21 at 10:00 UT detected flux from the position of the accreting millisecond pulsar SAX J1808.4-3658. The 2-10 keV flux was 10 mCrab. This appears to be the beginning of a new transient outburst (the last one began in June 2005). There is a small amount of on-source PCA data with high time resolution, but the pulsations were not detectable.