  We demonstrate the ability to excite atoms at well-defined, programmable
locations in a magneto-optical trap, either to the continuum (ionisation), or
to a Rydberg state. To this end, excitation laser light is shaped into
arbitrary intensity patterns with a spatial light modulator. These optical
patterns are sensitive to aberrations of the phase of the light field, occuring
while traversing the optical beamline. These aberrations are characterised and
corrected without observing the actual light field in the vacuum chamber.
