  We report on a lattice investigation of heavy quark momentum diffusion within
the pure SU(3) plasma above the deconfinement transition with the quarks
treated to leading order in the heavy mass expansion. We measure the relevant
"colour-electric" Euclidean correlator and based on several lattice spacing's
perform the continuum extrapolation. This is necessary not only to remove
cut-off effects but also the analytic continuation for the extraction of
transport coefficients is well-defined only when a continuous function of the
Euclidean time variable is available. We pay specific attention to scale
setting in SU(3). In particular we present our determination for the critical
temperature $T_c=1/({N_\tau}a) $ at values of $N_\tau \le 22$.
