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We report long-term simultaneous optical and (RXTE) X-ray observations of thesoft X-ray transient and low mass X-ray binary X1608-52 spanning from 1999 to2001. In addition to the usual X-ray outburst and quiescent states, X1608-52also exhibits an extended low intensity state during which the opticalcounterpart, QX Nor, is found to be about two magnitudes brighter than duringquiescence. We detect optical photometric variability on a possible period of0.5370 days with a semi-amplitude of ~0.27 mag in the I band. The modulationcould be orbital but is also consistent with a scenario invoking a superhumpwith decreasing period. Observations of QX Nor during quiescence indicate an Fto G type main sequence secondary while theoretical considerations argue for anevolved mass donor. Only an evolved mass donor would satisfy the condition forthe occurrence of superhumps.Comment: 26 pages, 10 figures, ApJ, in pres

A Closer Look at the Soft X‐Ray Transient X1608−52: Long‐Term Optical and X‐Ray Observations