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   PR # 21157
     We propose ASCA observations of three clusters of galaxies which are
    targets for the Sunyaev-Zeldovich (SZ) effect: Abell~959, Abell~1851,
    and Abell~1995. ASCA data will allow us to study the temperature and 
    density  profiles of these clusters. This will be essential to       
    interpret  SZ decrement radio data to be obtained from the Ryle      
    telescope and derive an unbiased value for the Hubble constant.      
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