Heliograph
A heliograph (from
Description
There were many heliograph types. Most heliographs were variants of the British Army Mance Mark V version (Fig.1). It used a mirror with a small unsilvered spot in the centre. The sender aligned the heliograph to the target by looking at the reflected target in the mirror and moving their head until the target was hidden by the unsilvered spot. Keeping their head still, they then adjusted the aiming rod so its cross wires bisected the target.[4] They then turned up the sighting vane, which covered the cross wires with a diagram of a cross, and aligned the mirror with the tangent and elevation screws so the small shadow that was the reflection of the unsilvered spot hole was on the cross target.[4] This indicated that the sunbeam was pointing at the target. The flashes were produced by a keying mechanism that tilted the mirror up a few degrees at the push of a lever at the back of the instrument. If the Sun was in front of the sender, its rays were reflected directly from this mirror to the receiving station. If the Sun was behind the sender, the sighting rod was replaced by a second mirror, to capture the sunlight from the main mirror and reflect it to the receiving station.[5][6] The U. S. Signal Corps heliograph mirror did not tilt. This type produced flashes by a shutter mounted on a second tripod (Fig 4).[5]
The heliograph had certain advantages. It allowed long distance communication without a fixed infrastructure, though it could also be linked to make a fixed network extending for hundreds of miles, as in the fort-to-fort network used for the Geronimo campaign. It was very portable, did not require any power source, and was relatively secure since it was invisible to those not near the axis of operation, and the beam was very narrow, spreading only 50 feet per mile of range. However, anyone in the beam with the correct knowledge could intercept signals without being detected.[3][7] In the Boer War, where both sides used heliographs, tubes were sometimes used to decrease the dispersion of the beam.[3] In some other circumstances, though, a narrow beam made it difficult to stay aligned with a moving target, as when communicating from shore to a moving ship, so the British issued a dispersing lens to broaden the heliograph beam from its natural diameter of 0.5 degrees to 15 degrees.[8]
The range of a heliograph depends on the opacity of the air and the effective collecting area of the mirrors. Heliograph mirrors ranged from one point five inches (3.8 cm) to 12 inches (30 cm) or more. Stations at higher altitudes benefit from thinner, clearer air, and are required in any event for great ranges, to clear the
History
The German professor
For example, one author in 1919 chose to "hazard the theory"[14] that the mainland signals Roman emperor Tiberius watched for from Capri[15] were mirror flashes, but admitted "there are no references in ancient writings to the use of signaling by mirrors", and that the documented means of ancient long-range visual telecommunications was by beacon fires and beacon smoke, not mirrors.
Similarly, the story that a shield was used as a heliograph at the Battle of Marathon is a modern myth,[16] originating in the 1800s. Herodotus never mentioned any flash.[17] What Herodotus did write was that someone was accused of having arranged to "hold up a shield as a signal".[18] Suspicion grew in the 1900s that the flash theory was implausible.[19] The conclusion after testing the theory was "Nobody flashed a shield at the Battle of Marathon".[20]
In a letter dated 3 June 1778,
The simple and effective instrument that Mance invented was to be an important part of military communications for more than 60 years. The usefulness of heliographs was limited to daytimes with strong sunlight, but they were the most powerful type of visual signalling device known. In pre-radio times heliography was often the only means of communication that could span ranges of as much as 100 miles with a lightweight portable instrument.[10]
In the United States military, by mid-1878, Colonel Nelson A. Miles had established a line of heliographs connecting Fort Keogh and Fort Custer, Montana, a distance of 140 miles (230 km).[27][28][29] In 1886, General Nelson A. Miles set up a network of 27 heliograph stations in Arizona and New Mexico during the hunt for Geronimo.[30] In 1890, Major W. J. Volkmar of the US Army demonstrated in Arizona and New Mexico the possibility of performing communication by heliograph over a heliograph network aggregating 2,000 miles in length.[31] The network of communication begun by General Miles in 1886, and continued by Lieutenant W. A. Glassford, was perfected in 1889 at ranges of 85, 88, 95, and 125 miles over a rugged and broken country, which was the stronghold of the Apache and other hostile Indian tribes.[10]
By 1887, heliographs in use included not only the British Mance and Begbie heliographs, but also the American Grugan, Garner and Pursell heliographs. The Grugan and Pursell heliographs used shutters, and the others used movable mirrors operated by a finger key. The Mance, Grugan and Pursell heliographs used two tripods, and the others one. The signals could either be momentary flashes, or momentary obscurations.[32] In 1888, the US Signal Service reviewed all of these devices, as well as the Finley Helio-Telegraph,[32] and finding none completely suitable, developed the US Signal Service heliograph, a two-tripod, shutter-based machine of 13+7⁄8 pounds (6.3 kg). total weight, and ordered 100 for a total cost of $4,205.[33] In 1893, the number of heliographs manufactured for the US Signal Service was 133.[34]
The heyday of the heliograph was probably the
In 1909, the use of heliography for forestry protection was introduced in the United States. By 1920 such use was widespread in the US and beginning in Canada, and the heliograph was regarded as "next to the telephone, the most useful communication device that is at present available for forest-protection services".[5] D.P. Godwin of the US Forestry Service invented a very portable (4.5 lb) heliograph of the single-tripod, shutter plus mirror type for forestry use.[5]
Immediately prior to the outbreak of World War I, the cavalry regiments of the Russian Imperial Army were still being trained in heliograph communications to augment the efficiency of their scouting and reporting roles.
During World War II, South African and Australian forces used the heliograph while fighting German forces in Libya and Egypt in 1941 and 1942.[2]
The heliograph remained standard equipment for military
Automated heliographs
Most heliographs of the 19th and 20th century were completely manual.[5] The steps of aligning the heliograph on the target, co-aligning the reflected sunbeam with the heliograph, maintaining the sunbeam alignment as the sun moved, transcribing the message into flashes, modulating the sunbeam into those flashes, detecting the flashes at the receiving end, and transcribing the flashes into the message, were all done manually.[5] One notable exception – many French heliographs used clockwork heliostats to automatically steer out the sun's motion. By 1884, all active units of the "Mangin apparatus" (a dual-mode French military field optical telegraph that could use either lantern or sunlight) were equipped with clockwork heliostats.[37] The Mangin apparatus with heliostat was still in service in 1917.[38][39][40] Proposals to automate both the modulation of the sunbeam (by clockwork) and the detection (by electrical selenium photodetectors, or photographic means) date back to at least 1882.[41] In 1961, the US Air Force was working on a space heliograph to signal between satellites[42]
In May 2012, "Solar Beacon" robotic mirrors designed at UC Berkeley were mounted on the towers of the Golden Gate bridge, and a web site set up[43] where the public could schedule times for the mirrors to signal with sun-flashes, entering the time and their latitude, longitude and altitude.[44] The solar beacons were later moved to Sather Tower at UC Berkeley.[45][46] By June 2012, the public could specify a "custom show" of up to 32 "on" or "off" periods of 4 seconds each, permitting the transmission of a few characters of Morse Code.[47] The designer described the Solar Beacon as a "heliostat", not a "heliograph".[44]
The first digitally controlled heliograph was designed and built in 2015.[48][49] It was a semi-finalist in the Broadcom MASTERS competition.[50]
See also
- Heliography, an early photographic process invented by Joseph Nicéphore Niépce around 1822
- Heliotrope (instrument)
- Operation On-Target, a Scouting program
- Signal lamp
- [[1]]
References
- ISBN 9781118563274.
- ^ ISBN 978-1851097326.
- ^ a b c d Major J. D. Harris WIRE AT WAR - Signals communication in the South African War 1899–1902. Retrieved on 1 June 2008. Discussion of heliograph use in the Boer War.
- ^ a b Signal Training. Vol. III. Pamphlet No. 2. Heliograph, 5-inch, Mark V. 1922. London: His Majesty's Stationery Office. 1922. pp. 10–13.
- ^ a b c d e f W. N. Millar (1920), Canadian Forestry Service. Methods of Communication Adapted to Forest Protection Google Books. Retrieved on 1 June 2008. pp. 160-181 are devoted to the heliograph, with diagrams of the British, American, and Godwin type.
- ^ Manual Of Instruction In Army Signaling 1886 Section III- Apparatus And Method Of Using It. Retrieved on 1 June 2008. Diagrams and instructions for British military heliograph (note British heraldry on cover).
- ^ Kipling, Rudyard A Code of Morals. The Kipling Society website. Retrieved on 1 June 2008.
- ^ Signals, Royal. "The Heliograph". Signalling Handbook (1905). Retrieved 15 April 2012.
- ^ Jacob, W.S. (November 1849). "On the Extinction of Light in the Atmosphere". Proceedings of the Royal Society of Edinburgh. 2: 272–273. Retrieved 19 May 2019.
- ^ a b c d e f Coe, Lewis The Telegraph: A History of Morse's Invention and Its Predecessors in the United States. Google Books. Retrieved on 1 June 2008.
- ISBN 0-88385-547-X.
- ^ "The Heliotrope". The Manchester Iris. 1 (32): 255–256. September 7, 1822. Retrieved 18 November 2012.
- ISBN 0818667826. Retrieved 18 November 2012.
- ^ Kingman, John (September 1919). "The Isle of Capri: An Imperial Residence and Probable Wireless Station of Ancient Rome". The National Geographic Magazine. p. 224. Retrieved 18 November 2012.
- ^ Suetonius (1796). The Lives of the First Twelve Caesars. G.G. and J. Robinson, Paternoster-Row. p. 296.
- ISBN 978-0300120851.
- ISBN 1841760005.
- ^ Herodotus (1920). "6.115.1, 6.121.1, 6.123.1,6.124,2". Herodotus, The Histories, with an English translation by A. D. Godley. Harvard University Press.
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- ISBN 978-0715375570.
- . Retrieved 16 June 2013.
- . Retrieved 2011-06-21.
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- . Retrieved June 21, 2011.
- ^ R. W. Burns (2004) Communications: An International History of the Formative Years. Google Books. Retrieved on 2 June 2008. pp. 192-196 discuss the heliograph.
- ISBN 0-292-74659-8.
- ^ Reade, Lt. Philip (January 1880). "About Heliographs". The United Service. 2: 91–108. Retrieved June 21, 2011.
- ^ "The Pacific Slope". Daily Alta California. 37 (12578): 5. 20 September 1884.
- ^ Rolak, Bruno. "General Miles' Mirrors The Heliograph in the Geromino Campaign of 1886". Fort Huachuca. Archived from the original on 17 February 2013. Retrieved 19 August 2018.
- ^ Greely, Adolphus (August 1899). "The Evolution of the Signal Corps". Ainslee's Magazine. IV (1): 17. Retrieved 31 March 2017.
- ^ a b An Improved Method in the Art of Signalling for Military and Scientific Purposes, The American Helio-Telegraph and Signal Light Company, 1887, retrieved 1 June 2008.
- ^ Annual Report of the Chief Signal Officer of the Army to the Secretary of War, 1889, pp. 43–7, retrieved 3 June 2008.
- ^ Report of the Chief Signal Officer. U.S. G.P.O. 1893. p. 671.
- ISBN 978-1-59048-256-8.
- ISBN 9780700709564, retrieved 3 June 2008.
- ^ Ternant, A.-L. (1884). Les télégraphes (2nd ed.). Hachette. pp. 35–65.
- ^ Charles-La Vauzelle, Henri (1912). Instruction Pratique Sur L'Installation des Communications Optiques dans le Service De la Telegraphie Militaire: Premiere Partie, Communications Optiques de Campagne. pp. 30–32, 42–43.
- ^ BOUCHETHAL, J.L. (1916). "LA TÉLÉGRAPHIE OPTIQUE AUX ARMÉES". La Science et la Vie (28): 337–342.
- ^ "Ottoman Soldiers Mounting Signal Apparatus, 1917". Flickr. Ottoman Imperial Archives. Retrieved 7 September 2015.
- ^ "The Heliograph in Mauritius". Engineering. 34: 363. October 13, 1882.
- ^ Pursglove, S. David (1961). "Ancient Heliograph Goes Modern for Space Age". Science and Mechanics: 70. Archived from the original on May 25, 2011.
- ^ "Solar Beacon". Archived from the original on 30 May 2012. Retrieved 30 May 2012.
- ^ a b Boxall, Bettina. "Golden Gate Bridge is prepared for 75th birthday celebration". LA Now. Los Angeles Times.
- ^ Tuan, Lydia (10 September 2013). "Solar Beacon atop Campanile allows for safe observation of sunlight". The Daily Californian.
- ^ "Solar Beacon". Retrieved 7 September 2015.
- ^ Vallerga, John. "Custom Show Setting". Solar Beacon. Retrieved 28 June 2012.
- ^ "IPA Freshman's science fair project". Island Pacific Academy. 3 September 2015. Retrieved 6 September 2015.
- ^ Welch, Natalie. "Digital Heliograph". Retrieved 6 September 2015.
- ^ "2015 Broadcom MASTERS Semifinalists". Retrieved 5 September 2015.
Further reading
- Lewis Coe, Great Days of the Heliograph, Crown Point, 1987 OCLC 16902284
External links
- Heliography: Communicating with Mirrors Photographs of British, American and Portuguese heliographs.
- The Heliograph A description of the British Mance, Begbie and French LeSeurre heliographs with illustrations (1899)
- Eliografo Detailed color photographs of a World War 2 British Mance heliograph (Italian).
- "Heliograph" at the National Library of Australia: Trove; 100+ historical heliograph photographs at the Australian War Memorial and elsewhere
- Royal Signals Datasheet No. 2. The Heliograph (revised April 2003) Archived 2012-09-05 at the Wayback Machine
- CHAPTER IV THE HELIOGRAPH (PAGE 48 OF THE 1905 SIGNALLING HANDBOOK)
- Mance Mark V Heliograph Detailed photos of a British Mark V Heliograph and kit, links to patents. Clicking on visible photos reveals high resolution photos.
- The Heliograph in the Apache Wars
- Signals communication in the South African War 1899-1902
- Heliographs at the Museum of RetroTechnology