Signals Private Alec Aitken and the 72nd Regiment Signals Platoon using a heliograph to signal, 1912/1913. He was a stenographer in civilian life. There are three soldiers, one with binoculars, the other with a chart and Aitken in the middle with the heliograph. The caption states:" Using a heliograph to signal". Articles on Heliographs attached to Media A heliograph is a wireless solar telegraph that signals by flashes of sunlight (generally using Morse code) reflected by a mirror. The flashes are produced by momentarily pivoting the mirror, or by interrupting the beam with a shutter. The heliograph was a simple but effective instrument for instantaneous optical communication over long distances during the late 19th and early 20th century. Its main uses were military, survey and forest protection work. Heliographs were standard issue in the British and Australian armies until the 1960s, and were used by the Pakistani army as late as 1975.