heliograph

signaling device

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Last updated

June 11, 2026

Quick Summary

A heliograph is a signaling device that uses a mirror to flash the sun's rays, enabling communication over distances. This method of signaling is also referred to as heliography. The term "heliograph" was first used in 1877.12

Heliography can also refer to an early photographic process that created photoengravings on metal plates coated with asphalt, or more broadly, photography itself.2

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military communication
The advent of electrical signaling
…through the development of the heliograph. It employed two adjustable mirrors so arranged that a beam of light from the sun could be reflected in any direction. The beam was interrupted by a key-operated shutter that permitted the formation of the dots and dashes of the Morse code. Where climatic…
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…through the development of the heliograph. It employed two adjustable mirrors so arranged that a beam of light from the sun could be reflected in any direction. The beam was interrupted by a key-operated shutter that permitted the formation of the dots and dashes of the Morse code. Where climatic…
Read More

Sir Henry Christopher Mance
…and engineer who invented the heliograph, a signaling device that employs two mirrors to gather sunlight and send it to a prearranged spot as a coded series of short and long flashes.
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…and engineer who invented the heliograph, a signaling device that employs two mirrors to gather sunlight and send it to a prearranged spot as a coded series of short and long flashes.
Read More