  The radio frequency penetration depth was measured in the superconductor
(Ba$_{0.55}$K$_{0.45}$)Fe$_{2}$As$_{2}$ under pulsed magnetic fields extending
to 60 tesla and down to 14 K. Using these data we are able to infer a
$H_{c2}(T)$, $H-T$ phase diagram, for applied fields parallel and perpendicular
to the crystallographic c-axis. The upper critical field curvature is different
for the respective orientations but they each remain positive down to 14 K. The
upper critical field anisotropy is moderate, $\approx 3.5$ close to $T_c$, and
drops with the decrease of temperature, reaching $\approx 1.2$ at $14 K$. These
data and analysis indicate that (i) (Ba$_{0.55}$K$_{0.45}$)Fe$_{2}$As$_{2}$
anisotropy diminishes with temperature and has an unusual temperature
dependence, (ii) $H_{c2} (T=0)$ for this compound may easily approach fields of
75 tesla.
