Every day around the world ships at sea approach coastlines as they follow the course to their destination. In older times ships lacked technology such as radar and were dependent on their navigation skills taking sun and star sights and recognising the coast line from their charts and guide books. Then on more dangerous coasts light houses were constructed each with their own distinctive flashing light sequence. With lighthouse men ensuring they always emitted their signal. In todays world the lights still emit their signals and navigators still take bearings to check their position. Even though they have high quality radar and direction finding technology. They all require power? Frame measurement Height 57cm X 50cm