  Stereoscopic viewing of TeV gamma-ray air showers with systems of Imaging
Atmospheric Cherenkov Telescopes (IACTs) allows to reconstruct the origin of
individual primary particles with an accuracy of 0.1 degree or better. The
shower impact point can be determined within 15 meters. To actually achieve
this resolution, the pointing of the telescopes of an IACT system needs to be
controlled with high precision. For the HEGRA IACT system, a procedure to
calibrate telescope pointing was established, using bright stars distributed
over the sky as references. On the basis of these measurements, one determines
parameters of a correction function which is valid for the complete hemisphere.
After correction a pointing accuracy of 0.01 degree is achieved.
