Abstract: The invention provides a closed television system for viewing the pulsed laser beam machining of a workpiece said system including a TV camera tube which, in use, is pointed at the area of incidence of the laser beam on said workpiece, a rotary shutter in the optical path of said TV camera tube for intercepting intermittently the light passing along said optical path, and means for synchronising the pulsing of the laser and the rotation of said shutter so that, in use, said shutter prevents light from reaching said TV camera tube each time said laser is pulsed. The invention can be applied to conventional closed circuit television systems to produce a system for viewing the machining a workpiece with a pulsed laser beam without the bright light produced during such a machining operation permanently overloading the TV camera tube.