In a series of papers we investigate far-infrared emission from rich galaxy
clusters. Maps have been obtained by ISO at 60 mu m, 100 mu m, 135 mu m, a
nd 200 mu m using the PHT-C camera. Ground based imaging and spectroscopy w
ere also acquired. Here we present the results for the cooling flow cluster
Sersic 159-03. An infrared source coincident with the dominant cD galaxy i
s found. Some off-center sources are also present, but without any obvious
counterparts.