******************************************************                         
    PR # 31531                                                                   
     PG 1553+11 is one of the brightest BL Lacertae objects detected by          
      the Einstein IPC. We propose to study the source with ASCA to search       
       for flux and spectral variations. Studies of other BL Lacs have sho       
     wn that the dynamical behaviour of the X-ray emitting region is compl       
     ex. Current theories based on extensions to standard global models ar       
     e probably insufficient to explain many of the observed variability         
     properties. A study of PG 1553+11, known to be highly variable in the       
       optical and UV, will contribute greatly to our understanding of the       
     se  dynamically interesting objects.                                        
                                                                                 
                                                                                 
                                                                                 
  ******************************************************