  This paper presents a method to reconstruct the position of the line of sight
and orientation of the focal plane of the Planck satellite, which may be
expressed by the parameters of the effective boresight and roll angles,
respectively. The accuracy to which these parameters must be determined to
avoid compromising the reconstruction of the C_{\ell} power spectrum is
assessed. It is expected that the pointing reconstruction will be performed
using point source transits in the highest frequency channels, given their
smaller beam sizes. Estimates are made for the number of galactic and
extragalactic point sources visible by Planck in these channels. The ability of
the method presented here to reconstruct the pointing parameters to the
required accuracies using these point sources is investigated. It is found that
the scanning strategy employed and the actual orientation of the focal plane
both independently influence the available number of suitable point sources,
from which this method may successfully evaluate the pointing parameters. While
this paper focuses on the pointing reconstruction of the Planck satellite,
elements of the analysis presented here may be of use elsewhere.
