We discuss a new method of finding the cluster temperatures which is independent of distance and therefore very useful for distant clusters .
The hot gas of electrons in clusters of galaxies scatters and distorts the cosmic microwave background radiation in a well determined way .
This Sunyaev-Zel ’ dovich ( SZ ) effect is a useful tool for extracting information about clusters such as their peculiar radial velocity and optical depth .
Here we show how the temperature of the cluster can be inferred from the SZ effect , in principle without use of X-ray data .
We use recent millimetre observation of Abell 2163 to determine for the first time a cluster temperature using SZ observations only .
The result T _ { e } = 26 ^ { +34 } _ { -19 } keV at 68 % confidence level ( at 95 % c.l .
we find T > 1.5 keV ) is in reasonable agreement with the X-ray results , T _ { e } = 12.4 ^ { +2.8 } _ { -1.9 } keV .