Abstract: The invention provides a peripheral vision horizon device for use in projecting a light bar on the interior of an aircraft cockpit or the like to indicate pitch and roll, the light bar being located with reference to a datum in the cockpit. The device includes a housing having a first part attachable to the cockpit and a second part rotatably coupled to the first part for movement about a first axis which on assembly in the aircraft extends transversely of the cockpit. A lens carrier is rotatably coupled to the second part for rotation about a second axis which is at right angles to the first axis. A light source is contained in the housing and an optical system is coupled to the housing for directing light from the light source towards the lens carrier along the second axis. A lens of two-fold symmetry is mounted in the lens carrier transversely of the second axis for receiving said light and projecting a beam of light which strikes the interior of the cockpit to create the light bar.