  The Clementine Gnomon in the Basilica of Santa Maria degli Angeli in Rome has
been realized in 1702 with the aim to measure the variation of the obliquity of
the Earth axis along the forthcoming centuries. Since then the church and the
instrument undergone several restorations and the original conditions of the
pinhole changed. The measurements of the position of the image in the days
before and of the 2011 winter solstice with respect to the original markers
compared with the ephemerides gives us the North-South correction for the
position of the pinhole to be restored.
