<title>TNG rotator axes motion control</title>

Abstract

The TNG is an Italian 3.6 m Alt-Az telescope installed at La Palma international astronomical Observatory Roque de Los Muchachos. It is equipped with two Nasmyth foci where the instrumentation is permanently installed. The first one is devoted to imaging and to support adaptive optics equipment and the other is devoted to spectroscopy. At each of the two foci the rotation of the field implied by the Alt-Az mount of the telescope needs to be compensated by the movement of one of the two rotator axes. The drive and control system and the solutions adopted for the motion control are here briefly described.