Abstract: An optical correcting element using a lenticular membrane (1) stretched on a frame (2) the membrane being of a thickness less than that required to be self-supporting whereby radiation is passed even though material in a self-supporting form would obstruct the radiation, the correcting element (1, 2) being associated with a spherical mirror (3) or any form of mirror or lens and being independent or adhered to the surface of a mirror or lens.

Abstract: A method and means of scanning the image of a detector along a scan line in the field of view in which a moving auxiliary optical system is used to scan the image field of a primary spherical mirror optical system of wide angular field and inadequate definition and correcting the aberrations of the primary collecting system by means of the auxiliary optocal system.

Abstract: A portable high intensity lamp comprising of a housing having a lamp supported in it and also carrying a battery and a switch relay and circuitry to energize and de-energize the light source from the battery, and a remote control trigger device and connecting line to the circuitry within the housing arranged to be removably supported in the housing, means being provided to hold the trigger device in the housing during transport, the trigger having a test and also an energize switch to operate the circuitry in the housing to thereby energize the light source, the test circuit being arranged to cause flow of current insufficient to actuate the switch relay but sufficient to test continuity of the line and establishment of correct operating conditions of the circuitry and light source prior to energization.