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   PR # 21526
    We propose to observe 2 bright low redshift radio quiet quasars for  
    which an absorption edge (with tau~3 and tau=0.5 respectively) has   
    been observed from pointed observations with the ROSAT-PSPC. This    
    spectral feature is likely to be more complex than a single edge.The 
    ASCA spectra with their unprecedented resolution will allow one to   
    identify the transitions and measure line widths and line shifts,from
    which the physical conditions of the warm absorber can beobtained.Our
    first priority target is PG1404+226:in this object the flux decreased
    by a factor of 2 over 12 hours during the ROSAT pointed obsevations  
    and the energy of the strong edge moved from 1.03 to0.8 keV. Simula- 
    tions show that it will be possible to do time resolved spectroscopy 
   with a time resolution of 5 ki
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