A solar tracker with a torsional vibration damping device, comprising: a rotating shaft having a longitudinal axis; a pivoting assembly fixedly connected to the rotating shaft, the pivoting assembly having solar panels arranged to receive solar radiation; a fixed structure comprising a plurality of support elements (4, 5, 6) rotationally supporting the rotating shaft at a plurality of support points distributed therealong; a motor-reducer assembly operatively connected to rotate the rotating shaft about the longitudinal axis so as to track the sun; and a torsional vibration damping device having one moving member rigidly connected to the rotating shaft to move therewith; the motor-reducer assembly is cinematically connected to the rotating shaft at a motor connection point; the motor-reducer assembly has an irreversible reducer which provides retention against torsional vibration of the rotating shaft at the motor connection point; characterized in that: the torsional vibration damping device further comprises a stationary member which is rigidly attached to the fixed structure; the moving member of the torsional vibration damping device is rigidly connected to the rotating shaft at a damper connection point spaced apart from the motor connection point and arranged to move close to the stationary member without contact; and one member selected between the moving member and the stationary member comprises magnetic field-generating elements and the other member selected between the moving member and the stationary member comprises a section made of an electrically conductive, non-ferromagnetic material, relative movement between the magnetic field-generating elements and the section made of an electrically conductive, non-ferromagnetic material producing a damping torque by Foucault currents effect. a rotating shaft having a longitudinal axis; a pivoting assembly fixedly connected to the rotating shaft, the pivoting assembly having solar panels arranged to receive solar radiation; a fixed structure comprising a plurality of support elements (4, 5, 6) rotationally supporting the rotating shaft at a plurality of support points distributed therealong; a motor-reducer assembly operatively connected to rotate the rotating shaft about the longitudinal axis so as to track the sun; and a torsional vibration damping device having one moving member rigidly connected to the rotating shaft to move therewith; the motor-reducer assembly is cinematically connected to the rotating shaft at a motor connection point; the motor-reducer assembly has an irreversible reducer which provides retention against torsional vibration of the rotating shaft at the motor connection point; characterized in that: the torsional vibration damping device further comprises a stationary member which is rigidly attached to the fixed structure; the moving member of the torsional vibration damping device is rigidly connected to the rotating shaft at a damper connection point spaced apart from the motor connection point and arranged to move close to the stationary member without contact; and one member selected between the moving member and the stationary member comprises magnetic field-generating elements and the other member selected between the moving member and the stationary member comprises a section made of an electrically conductive, non-ferromagnetic material, relative movement between the magnetic field-generating elements and the section made of an electrically conductive, non-ferromagnetic material producing a damping torque by Foucault currents effect. the torsional vibration damping device further comprises a stationary member which is rigidly attached to the fixed structure; the moving member of the torsional vibration damping device is rigidly connected to the rotating shaft at a damper connection point spaced apart from the motor connection point and arranged to move close to the stationary member without contact; and one member selected between the moving member and the stationary member comprises magnetic field-generating elements and the other member selected between the moving member and the stationary member comprises a section made of an electrically conductive, non-ferromagnetic material, relative movement between the magnetic field-generating elements and the section made of an electrically conductive, non-ferromagnetic material producing a damping torque by Foucault currents effect.