postscript
4 The Hubble diagram...
Abstract...
References...
We can conclude that the cluster CL 0016+16 provides an estimate for the Hubble
constant of 
where the errors
include systematic and random components only, and where a further
orientation-dependent error of about 
is
likely from the unknown three-dimensional structure of the cluster. The
ensemble average Hubble constant, based on the SZ effect Hubble diagram to
date, is 
, where the error takes some
account of the uncertain systematic effects associated with orientation bias
and calibration uncertainties in the data.
Much better-controlled cluster samples, and better-calibrated X-ray and SZ
effect data are needed to reduce the error on 
further. Further clusters
at 
are needed if this technique is to constrain 
.