1,021,867. Television. ENGLISH ELECTRIC AVIATION Ltd. Oct. 28, 1964 [Oct. 28, 1963], No. 42504/63. Heading H4F. An aircraft having in its airframe a window 9 which is transparent to visible and infra-red radiation from an object to be identified, e.g. a foreign aircraft 3, has mounted within the airframe an angularly adjustable plane reflector 8 arranged to reflect radiation passing through the window, a radar or infra-red tracking equipment 4, 5 for following the course of the object to be identified, a servo-mechanism 6 controlled by the tracking equipment to drive the reflector 8 through an angle which is half the relative angular movement of the object so that the beam of radiant energy received from the object is reflected along a fixed path to a telescope objective 11, e.g. a parabolic mirror, from where it is reflected back through holes in the centre of the reflector 8 and servomechanism 6 and focused directly on to the photo-cathode of a vidicon camera 12. A receiver 14 may be connected by a closed circuit television link 13 to camera 12, the receiver having a manual control 15 for centralization, by way of further servo-commands, and magnification of the image. The dimensions of the object may be ascertained by comparison with a scale superimposed electroncally on the display, the overall magnification being known and the range of the object being available in the radar. In a further embodiment, Fig. 2, shown, a laser is used to illuminate the object, its narrow coherent light beam passing through a hole in mirror 11 and being reflected from plane mirror 8 on to the object.