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    PR # 31553                                                                   
     As the microwave background (MWB) photons travel towards us through r       
     ich clusters of galaxies, they are scattered to higher energies by th       
     e hot gas in the clusters. The resulting spectral distortion is calle       
     d the Sunyaev-Zeldovich (SZ) effect. The cosmological importance of t       
     he SZ effect is that, when coupled with an X-ray determination of the       
      temperature and density profile of the hot scattering gas, it is pos       
     sible to directly deduce the scale size of the universe, ie the Hubbl       
     e constant. Elsewhere we propose to make the SZ observations. Here we       
      propose to make the vital X-ray measurements, which make full use of       
      the capabilities of ASCA, on an excellent SZ candidate cluster, A177       
     4.                                                                          
                                                                                 
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