
A heliograph () is a solar telegraph system that signals by flashes of sunlight (generally using
Morse code
Morse code is a telecommunications method which Character encoding, encodes Written language, text characters as standardized sequences of two different signal durations, called ''dots'' and ''dashes'', or ''dits'' and ''dahs''. Morse code i ...
from the 1840s) reflected by a
mirror
A mirror, also known as a looking glass, is an object that Reflection (physics), reflects an image. Light that bounces off a mirror forms an image of whatever is in front of it, which is then focused through the lens of the eye or a camera ...
. 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
Optical communication, also known as optical telecommunication, is communication at a distance using light to carry information. It can be performed visually or by using electronic devices. The earliest basic forms of optical communication date ...
over long distances during the late 19th and early 20th centuries.[ Its main uses were military, ]surveying
Surveying or land surveying is the technique, profession, art, and science of determining the land, terrestrial Plane (mathematics), two-dimensional or Three-dimensional space#In Euclidean geometry, three-dimensional positions of Point (geom ...
and forest protection
Forest protection is a branch of forestry which is concerned with the preservation or improvement of a forest and prevention and control of damage to forest by natural or man made causes like forest fires, plant pests, and adverse climatic con ...
work. Heliographs were standard issue in the British and Royal Australian armies until the 1960s, and were used by the Pakistani army as late as 1975.
Description
There were many heliograph types. Most heliographs were variants of the British Army
The British Army is the principal Army, land warfare force of the United Kingdom. the British Army comprises 73,847 regular full-time personnel, 4,127 Brigade of Gurkhas, Gurkhas, 25,742 Army Reserve (United Kingdom), volunteer reserve perso ...
Mance Mark V version (Fig.1). It used a flat round 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. 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. 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.[Manual Of Instruction In Army Signaling 1886 Section III- Apparatus And Method Of Using It](_blank)
Retrieved on 1 June 2008. Diagrams and instructions for British military heliograph (note British heraldry
Heraldry is a discipline relating to the design, display and study of armorial bearings (known as armory), as well as related disciplines, such as vexillology, together with the study of ceremony, Imperial, royal and noble ranks, rank and genealo ...
emblem on cover). The U.S. Army's Signal Corps heliograph used a flat square mirror that did not tilt. This type produced flashes by a shutter mounted on a second tripod (Fig 4).[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.
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
Gerónimo (, ; June 16, 1829 – February 17, 1909) was a military leader and medicine man from the Bedonkohe band of the Ndendahe Apache people. From 1850 to 1886, Geronimo joined with members of three other Central Apache bands the Tchihen ...
military 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 per of range. However, anyone in the beam with the correct knowledge could intercept signals without being detected.[Kipling, Rudyar]
A Code of Morals
The Kipling Society website. Retrieved on 1 June 2008. In the Second Boer War
The Second Boer War (, , 11 October 189931 May 1902), also known as the Boer War, Transvaal War, Anglo–Boer War, or South African War, was a conflict fought between the British Empire and the two Boer republics (the South African Republic and ...
(1899–1902) in South Africa, where both sides used heliographs, tubes were sometimes used to decrease the dispersion of the beam.[Major J. D. Harri]
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. 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.
The range of a heliograph depends on the opacity of the air and the effective collecting area of the mirrors. Heliograph mirrors ranged from or more. Stations at higher altitudes benefit from thinner, clearer air, and are required in any event for great ranges, to clear the curvature of the Earth
Spherical Earth or Earth's curvature refers to the approximation of the figure of the Earth as a sphere. The earliest documented mention of the concept dates from around the 5th century BC, when it appears in the writings of Greek philosophers. ...
. A good approximation for ranges of is that the flash of a circular mirror is visible to the naked eye at a distance of for each inch of mirror diameter, and farther apart seen with a telescope
A telescope is a device used to observe distant objects by their emission, Absorption (electromagnetic radiation), absorption, or Reflection (physics), reflection of electromagnetic radiation. Originally, it was an optical instrument using len ...
. The world record distance was established by a detachment of U.S. Army signal sergeants by the inter-operation of stations in North America on Mount Ellen, (Utah
Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...
), and Mount Uncompahgre, (Colorado
Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas ...
), apart on 17 September 1894, with Army Signal Corps heliographs carrying mirrors only 8 inches (20 cm) on a side.[Coe, Lewi]
The Telegraph: A History of Morse's Invention and Its Predecessors in the United States
Google Books. Retrieved on 1 June 2008.
History
The German professor Carl Friedrich Gauss
Johann Carl Friedrich Gauss (; ; ; 30 April 177723 February 1855) was a German mathematician, astronomer, geodesist, and physicist, who contributed to many fields in mathematics and science. He was director of the Göttingen Observatory and ...
(1777–1855), of the University of Göttingen
The University of Göttingen, officially the Georg August University of Göttingen (, commonly referred to as Georgia Augusta), is a Public university, public research university in the city of Göttingen, Lower Saxony, Germany. Founded in 1734 ...
developed and used a predecessor of the heliograph (the heliotrope) in 1821. His device directed a controlled beam of sunlight to a distant station to be used as a marker for geodetic survey
Geodesy or geodetics is the science of measuring and representing the Figure of the Earth, geometry, Gravity of Earth, gravity, and Earth's rotation, spatial orientation of the Earth in Relative change, temporally varying Three-dimensional spac ...
work, and was suggested as a means of telegraphic communications. This is the first reliably documented heliographic device, despite much speculation about possible ancient incidents of sun-flash signalling, and the documented existence of other forms of ancient optical telegraphy.
For example, one author in 1919 chose to "hazard the theory" that the Italian mainland signals from the capital of Rome
Rome (Italian language, Italian and , ) is the capital city and most populated (municipality) of Italy. It is also the administrative centre of the Lazio Regions of Italy, region and of the Metropolitan City of Rome. A special named with 2, ...
that ancient Roman emperor Tiberius
Tiberius Julius Caesar Augustus ( ; 16 November 42 BC – 16 March AD 37) was Roman emperor from AD 14 until 37. He succeeded his stepfather Augustus, the first Roman emperor. Tiberius was born in Rome in 42 BC to Roman politician Tiberius Cl ...
(42 B.C.-A.D.37, reigned A.D.14 to 37), watched for from his imperial retreat on the island of Capri
Capri ( , ; ) is an island located in the Tyrrhenian Sea off the Sorrento Peninsula, on the south side of the Gulf of Naples in the Campania region of Italy. A popular resort destination since the time of the Roman Republic, its natural beauty ...
. 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 ancient famous Battle of Marathon
The Battle of Marathon took place in 490 BC during the first Persian invasion of Greece. It was fought between the citizens of Athens (polis), Athens, aided by Plataea, and a Achaemenid Empire, Persian force commanded by Datis and Artaph ...
between the Greeks
Greeks or Hellenes (; , ) are an ethnic group and nation native to Greece, Greek Cypriots, Cyprus, Greeks in Albania, southern Albania, Greeks in Turkey#History, Anatolia, parts of Greeks in Italy, Italy and Egyptian Greeks, Egypt, and to a l ...
and Persians
Persians ( ), or the Persian people (), are an Iranian ethnic group from West Asia that came from an earlier group called the Proto-Iranians, which likely split from the Indo-Iranians in 1800 BCE from either Afghanistan or Central Asia. They ...
in 490 B.C. is also unfortunately a modern myth, originating in the 1800s. The ancient historian Herodotus
Herodotus (; BC) was a Greek historian and geographer from the Greek city of Halicarnassus (now Bodrum, Turkey), under Persian control in the 5th century BC, and a later citizen of Thurii in modern Calabria, Italy. He wrote the '' Histori ...
never mentioned any flash. What Herodotus did write was that someone was accused of having arranged to "hold up a shield as a signal". Suspicion grew in the later 1900s, that the flash theory was implausible. The conclusion after testing the theory was "Nobody flashed a shield at the Battle of Marathon".
In a letter dated 3 June 1778, John Norris, High Sheriff of Buckinghamshire
Buckinghamshire (, abbreviated ''Bucks'') is a Ceremonial counties of England, ceremonial county in South East England and one of the home counties. It is bordered by Northamptonshire to the north, Bedfordshire to the north-east, Hertfordshir ...
, England, notes: "Did this day heliograph intelligence from Dr enjaminFranklin in Paris to Wycombe". However, there is little evidence that "heliograph" here is other than a misspelling of "holograph
An autograph or holograph is a manuscript or document written in its author's or composer's hand. The meaning of " autograph" as a document penned entirely by the author of its content (as opposed to a typeset document or one written by a copy ...
". The term "heliograph" for solar telegraphy did not enter the English language until the 1870s—even the word "telegraphy
Telegraphy is the long-distance transmission of messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. Thus flag semaphore is a method of telegraphy, whereas pi ...
" was not coined until the 1790s.
Henry Christopher Mance
Sir Henry Christopher Mance, (6 September 1840 – 21 April 1926) was a British electrical engineer and a former president of the Institution of Electrical Engineers. He was knighted for developing the heliograph.
Career
Born in Exeter, he was ...
(1840–1926), of the British Government's Persian Gulf Telegraph Department, developed the first widely accepted heliograph about 1869, while stationed at Karachi
Karachi is the capital city of the Administrative units of Pakistan, province of Sindh, Pakistan. It is the List of cities in Pakistan by population, largest city in Pakistan and 12th List of largest cities, largest in the world, with a popul ...
(now in modern Pakistan
Pakistan, officially the Islamic Republic of Pakistan, is a country in South Asia. It is the List of countries and dependencies by population, fifth-most populous country, with a population of over 241.5 million, having the Islam by country# ...
) in the then Bombay Presidency of British India
The provinces of India, earlier presidencies of British India and still earlier, presidency towns, were the administrative divisions of British governance in South Asia. Collectively, they have been called British India. In one form or another ...
. Mance was familiar with heliotropes by their use earlier for the mapping project of the Great Trigonometrical Survey
The Great Trigonometrical Survey of India was a project that aimed to carry out a survey across the Indian subcontinent with scientific precision. It was begun in 1802 by the British infantry officer William Lambton, under the auspices of t ...
of India (done 1802–1871). The Mance Heliograph was operated easily by one man, and since it weighed about , the operator could readily carry the device and its supporting tripod. The British Army tested the heliograph in India at a range of with favorable results. During the Jowaki Afridi expedition sent by the British-Indian government in 1877, the heliograph was first tested in war.[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.
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 with a lightweight portable instrument.
In the United States military
The United States Armed Forces are the Military, military forces of the United States. U.S. United States Code, federal law names six armed forces: the United States Army, Army, United States Marine Corps, Marine Corps, United States Navy, Na ...
, by mid-1878, a younger Colonel Nelson A. Miles
Nelson Appleton Miles (August 8, 1839 – May 15, 1925) was a United States Army officer who served in the American Civil War (1861–1865), the later American Indian Wars (1840–1890), and the Spanish–American War,
(1898). From 1895 to 1903 ...
had established a line of heliographs connecting far-flung military outposts of Fort Keogh
Fort Keogh is a former United States Army post located at the western edge of modern Miles City, Montana, Miles City, in the U.S. state of Montana. It is situated on the south bank of the Yellowstone River, at the mouth of the Tongue River (Mont ...
and Fort Custer, in the northern Montana Territory
The Territory of Montana was an organized incorporated territory of the United States that existed from May 26, 1864, until November 8, 1889, when it was admitted as the 41st state in the Union as the state of Montana.
Original boundaries
...
, a distance of . In 1886, United States Army
The United States Army (USA) is the primary Land warfare, land service branch of the United States Department of Defense. It is designated as the Army of the United States in the United States Constitution.Article II, section 2, clause 1 of th ...
now General Nelson A. Miles
Nelson Appleton Miles (August 8, 1839 – May 15, 1925) was a United States Army officer who served in the American Civil War (1861–1865), the later American Indian Wars (1840–1890), and the Spanish–American War,
(1898). From 1895 to 1903 ...
(1839–1925), set up a network of 27 heliograph stations in the Arizona
Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...
and New Mexico
New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...
territories of the old Southwest
The points of the compass are a set of horizontal, radially arrayed compass directions (or azimuths) used in navigation and cartography. A '' compass rose'' is primarily composed of four cardinal directions—north, east, south, and west— ...
during the extended campaign and hunt for the native Apache
The Apache ( ) are several Southern Athabaskan language-speaking peoples of the Southwestern United States, Southwest, the Southern Plains and Northern Mexico. They are linguistically related to the Navajo. They migrated from the Athabascan ho ...
renegade chief / guerrilla warfare leader Geronimo
Gerónimo (, ; June 16, 1829 – February 17, 1909) was a military leader and medicine man from the Bedonkohe band of the Ndendahe Apache people. From 1850 to 1886, Geronimo joined with members of three other Central Apache bands the Tchihen ...
(1829–1909). In 1890, now little-known Major W.J. Volkmar of the U.S. Army demonstrated in the Arizona
Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...
and New Mexico
New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...
territories, the possibility of performing communication by heliograph over a heliograph network aggregating in length. The network of communication begun by General Miles in 1886, and continued by unsung and now unfortunately relatively unknown Lieutenant W. A. Glassford, was perfected in 1889 at ranges of over a rugged and broken country, which was the stronghold of the Apache
The Apache ( ) are several Southern Athabaskan language-speaking peoples of the Southwestern United States, Southwest, the Southern Plains and Northern Mexico. They are linguistically related to the Navajo. They migrated from the Athabascan ho ...
, Commanche
The Comanche (), or Nʉmʉnʉʉ (, 'the people'), are a Native American tribe from the Southern Plains of the present-day United States. Comanche people today belong to the federally recognized Comanche Nation, headquartered in Lawton, Oklahoma ...
and other hostile native Indian tribes.
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.[.] In 1888, the U.S. Army Signal Corps reviewed all of these devices, as well as the Finley Helio-Telegraph, and finding none completely suitable, developed its own instrument of the U.S. Army Signal Corps heliograph, a two-tripod, shutter-based machine of total weight, and ordered 100, for a total cost of $4,205.[.] By 1893, the number of heliographs manufactured for the American Army Signal Corps was 133.
The heyday of the heliograph was probably the Second Boer War
The Second Boer War (, , 11 October 189931 May 1902), also known as the Boer War, Transvaal War, Anglo–Boer War, or South African War, was a conflict fought between the British Empire and the two Boer republics (the South African Republic and ...
of the 1890s and early 1900s in South Africa, where it was much used by both the British and the native immigrant Boers
Boers ( ; ; ) are the descendants of the proto Afrikaans-speaking Free Burghers of the eastern Cape frontier in Southern Africa during the 17th, 18th, and 19th centuries. From 1652 to 1795, the Dutch East India Company controlled the Dutch ...
. The terrain and climate, as well as the nature of the campaign, made heliography a logical choice. For night communications, the British used some large signal lamp
Signal lamp training during World War II
A signal lamp (sometimes called an Aldis lamp or a Morse lamp) is a visual signaling device for optical communication by flashes of a lamp, typically using Morse code. The idea of flashing dots and dashes ...
s, brought inland on railroad cars, and equipped with leaf-type shutters for keying a beam of light into dots and dashes. During the early stages of the war, the British Army
The British Army is the principal Army, land warfare force of the United Kingdom. the British Army comprises 73,847 regular full-time personnel, 4,127 Brigade of Gurkhas, Gurkhas, 25,742 Army Reserve (United Kingdom), volunteer reserve perso ...
garrisons were besieged in Kimberley
Kimberly or Kimberley may refer to:
Places and historical events
Australia
Queensland
* Kimberley, Queensland, a coastal locality in the Shire of Douglas
South Australia
* County of Kimberley, a cadastral unit in South Australia
Ta ...
, along with the sieges of Ladysmith, and at Mafeking
Mahikeng (Tswana for "Place of Rocks"), formerly known as Mafikeng and alternatively known as Mafeking (, ), is the capital city of the North West province of South Africa.
Close to South Africa's border with Botswana, Mafikeng is northeast o ...
. With land wire telegraph
Telegraphy is the long-distance transmission of messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. Thus flag semaphore is a method of telegraphy, whereas ...
lines cut, the only contact with the outside world was via light-beam communication, helio by day, and signal lamps at night.
In 1909, the use of heliography for forestry protection was introduced by the United States Forestry Service
The United States Forest Service (USFS) is an agency within the U.S. Department of Agriculture. It administers the nation's 154 national forests and 20 national grasslands covering of land. The major divisions of the agency are the Chief's O ...
in the western States. By 1920, such use was widespread in the US and beginning in the neighboring Dominion of Canada
While a variety of theories have been postulated for the name of Canada, its origin is now accepted as coming from the St. Lawrence Iroquoian word , meaning 'village' or 'settlement'. In 1535, indigenous inhabitants of the present-day Quebec C ...
to the north, and the heliograph was regarded as "next to the telephone, the most useful communication device that is at present available for forest-protection services". D.P. Godwin of the U.S. Forestry Service invented a very portable () heliograph of the single-tripod, shutter plus mirror type for forestry use.
Immediately prior to the outbreak of World War I
World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...
(1914–1918), the mounted cavalry regiments of the Russian Imperial Army
The Imperial Russian Army () was the army of the Russian Empire, active from 1721 until the Russian Revolution of 1917. It was organized into a standing army and a state militia. The standing army consisted of Regular army, regular troops and ...
in the Russian Empire
The Russian Empire was an empire that spanned most of northern Eurasia from its establishment in November 1721 until the proclamation of the Russian Republic in September 1917. At its height in the late 19th century, it covered about , roughl ...
were still being trained in heliograph communications to augment the efficiency of their scouting and reporting roles. Following the two Russian Revolutions of 1917
The Russian Revolution was a period of political and social change in Russia, starting in 1917. This period saw Russia abolish its monarchy and adopt a socialist form of government following two successive revolutions and a civil war. It ...
, the revolutionary Bolshevik
The Bolsheviks, led by Vladimir Lenin, were a radical Faction (political), faction of the Marxist Russian Social Democratic Labour Party (RSDLP) which split with the Mensheviks at the 2nd Congress of the Russian Social Democratic Labour Party, ...
/ Communist
Communism () is a sociopolitical, philosophical, and economic ideology within the socialist movement, whose goal is the creation of a communist society, a socioeconomic order centered on common ownership of the means of production, di ...
units of their Red Army
The Workers' and Peasants' Red Army, often shortened to the Red Army, was the army and air force of the Russian Soviet Republic and, from 1922, the Soviet Union. The army was established in January 1918 by a decree of the Council of People ...
during the subsequent Russian Civil War
The Russian Civil War () was a multi-party civil war in the former Russian Empire sparked by the 1917 overthrowing of the Russian Provisional Government in the October Revolution, as many factions vied to determine Russia's political future. I ...
of 1918–1922, made use of a series of heliograph stations to disseminate intelligence efficiently. This continued even a decade later about counter-revolutionary basmachi
The Basmachi movement (, derived from ) was an uprising against Imperial Russian and Soviet rule in Central Asia by rebel groups inspired by Islamic beliefs. It has been called "probably the most important movement of opposition to Soviet rul ...
rebel movements in Central Asia's Turkestan
Turkestan,; ; ; ; also spelled Turkistan, is a historical region in Central Asia corresponding to the regions of Transoxiana and East Turkestan (Xinjiang). The region is located in the northwest of modern day China and to the northwest of its ...
region in 1926.[.]
During World War II
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
(1939–1945), Union of South Africa
The Union of South Africa (; , ) was the historical predecessor to the present-day South Africa, Republic of South Africa. It came into existence on 31 May 1910 with the unification of the British Cape Colony, Cape, Colony of Natal, Natal, Tra ...
and Royal Australian military forces used the heliograph while fighting enemy Nazi German
Nazi Germany, officially known as the German Reich and later the Greater German Reich, was the German state between 1933 and 1945, when Adolf Hitler and the Nazi Party controlled the country, transforming it into a totalitarian dictat ...
and Fascist Italian
Italian fascism (), also called classical fascism and Fascism, is the original fascist ideology, which Giovanni Gentile and Benito Mussolini developed in Italy. The ideology of Italian fascism is associated with a series of political parties le ...
forces along the southern coast of the Mediterranean Sea
The Mediterranean Sea ( ) is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern Eur ...
in Libya
Libya, officially the State of Libya, is a country in the Maghreb region of North Africa. It borders the Mediterranean Sea to the north, Egypt to Egypt–Libya border, the east, Sudan to Libya–Sudan border, the southeast, Chad to Chad–L ...
and western Egypt
Egypt ( , ), officially the Arab Republic of Egypt, is a country spanning the Northeast Africa, northeast corner of Africa and Western Asia, southwest corner of Asia via the Sinai Peninsula. It is bordered by the Mediterranean Sea to northe ...
with fellow defending British military in the desert North African campaign
The North African campaign of World War II took place in North Africa from 10 June 1940 to 13 May 1943, fought between the Allies and the Axis Powers. It included campaigns in the Libyan and Egyptian deserts (Western Desert campaign, Desert Wa ...
in 1940, 1941 and 1942.[
The heliograph remained standard equipment for military ]signaller
A signaller, signalman, colloquially referred to as a radioman or signaleer in the armed forces is a specialist soldier, sailor or airman responsible for military communications. Signallers, a.k.a. Combat Signallers or signalmen or women, are ...
s in the Royal Australian and British armies
The British Armed Forces are the unified military forces responsible for the defence of the United Kingdom, its Overseas Territories and the Crown Dependencies. They also promote the UK's wider interests, support international peacekeeping eff ...
until the 1940s, where it was considered a "low probability of intercept" type of communication. The Canadian Army
The Canadian Army () is the command (military formation), command responsible for the operational readiness of the conventional ground forces of the Canadian Armed Forces. It maintains regular forces units at bases across Canada, and is also re ...
was the last major military force to have the heliograph as an issue item. By the time the mirror instruments were retired, they were seldom used for signalling. However, as recently as the 1980s, heliographs were used by insurgent Afghan mujahedeen forces during the Soviet invasion of Afghanistan
The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a transcontinental country that spanned much of Eurasia from 1922 until it dissolved in 1991. During its existence, it was the largest country by are ...
in 1978–1979. Signal mirrors are still included in survival kit
A survival kit is a package of basic tools and supplies prepared as an aid to survival skills, survival in an emergency. Civil and military aircraft, lifeboat (shipboard), lifeboats, and spacecraft are equipped with survival kits.
Survival ki ...
s for emergency signaling to search and rescue
Search and rescue (SAR) is the search for and provision of aid to people who are in distress or imminent danger. The general field of search and rescue includes many specialty sub-fields, typically determined by the type of terrain the search ...
aircraft.[
]
Automated heliographs
Most heliographs of the 19th and 20th centuries were completely manual. 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. 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 Army
The French Army, officially known as the Land Army (, , ), is the principal Army, land warfare force of France, and the largest component of the French Armed Forces; it is responsible to the Government of France, alongside the French Navy, Fren ...
military field optical telegraph that could use either lantern or sunlight) were equipped with clockwork heliostats. The Mangin apparatus with heliostat was still in service in 1917. 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. In 1961, the United States Air Force
The United States Air Force (USAF) is the Air force, air service branch of the United States Department of Defense. It is one of the six United States Armed Forces and one of the eight uniformed services of the United States. Tracing its ori ...
was working on a space heliograph to signal between satellites
In May 2012, "Solar Beacon" robotic mirrors designed at the University of California at Berkeley
The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a public land-grant research university in Berkeley, California, United States. Founded in 1868 and named after the Anglo-Irish philosopher George Berkele ...
were mounted on the twin towers of the Golden Gate Bridge
The Golden Gate Bridge is a suspension bridge spanning the Golden Gate, the strait connecting San Francisco Bay and the Pacific Ocean in California, United States. The structure links San Francisco—the northern tip of the San Francisco Peni ...
at the entrance to San Francisco Bay
San Francisco Bay (Chochenyo language, Chochenyo: 'ommu) is a large tidal estuary in the United States, U.S. state of California, and gives its name to the San Francisco Bay Area. It is dominated by the cities of San Francisco, California, San ...
, and a web site set up where the public could schedule times for the mirrors to signal with sun-flashes, entering the time and their latitude, longitude and altitude. The solar beacons were later moved to Sather Tower at the U.C. – Berkeley campus. 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. The designer described the Solar Beacon as a "heliostat", not a "heliograph".
The first digitally controlled heliograph was designed and built in 2015. It was a semi-finalist in the Broadcom MASTERS competition.
See also
* Heliography
Heliography is an early photographic process, based on the hardening of bitumen in sunlight. It was invented by Nicéphore Niépce around 1822. Niépce used the process to make the earliest known surviving photograph from nature, '' View from ...
, an early photographic process invented by Joseph Nicéphore Niépce around 1822
* Heliotrope (instrument)
The heliotrope is an instrument that uses a mirror to reflect sunlight over great distances to mark the positions of participants in a land Surveying, survey. The heliotrope was invented in 1821 by the Germany, German mathematician Carl Fried ...
* Operation On-Target
Operation On-Target is a high adventure Scouting activity. It was created as a Varsity Scout program activity, open to Venturers and older Boy Scouts. It has continued since the disbanding of the Varsity Scout program at the end of 2017. The ...
, a Scouting program
* Signal lamp
Signal lamp training during World War II
A signal lamp (sometimes called an Aldis lamp or a Morse lamp) is a visual signaling device for optical communication by flashes of a lamp, typically using Morse code. The idea of flashing dots and dashes ...
References
Further reading
* Lewis Coe, ''Great Days of the Heliograph'', Crown Point, 1987
External links
Heliography: Communicating with Mirrors
Photographs of British, American and Portuguese heliographs.
A description of the British Mance, Begbie and French LeSeurre heliographs with illustrations (1899)
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
* ttps://web.archive.org/web/20121014135758/http://home.arcor.de/royal-signals/page24/page28/page28.html 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.
at the Museum of RetroTechnology
{{Morse code
History of telecommunications
Telegraphy
Optical communications