  A pulsar beam passing close to a black hole can provide a probe of very
strong gravitational fields even if the pulsar itself is not in a strong field
region. In the case that the spin of the hole can be ignored, we have
previously shown that all strong field effects on the beam can be understood in
terms of two "universal" functions, $F(\phi_{\rm in})$ and $T(\phi_{\rm in})$
of the angle of beam emission $\phi_{\rm in}$; these functions are universal in
that they depend only on a single parameter, the pulsar/black hole distance
from which the beam is emitted. Here we apply this formalism to general
pulsar-hole-observer geometries, with arbitrary alignment of the pulsar spin
axis and arbitrary pulsar beam direction and angular width. We show that the
analysis of the observational problem has two distinct elements: (i) the
computation of the location and trajectory of an observer-dependent "keyhole"
direction of emission in which a signal can be received by the observer; (ii)
the determination of an annulus that represents the set of directions
containing beam energy. Examples of each are given along with an example of a
specific observational scenario.

Astrophysics of Galaxies