A heliograph (helios (Greek: ἥλιος), meaning "sun", and graphein (γράφειν), meaning "write") is a wireless 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.[1] The heliograph was a simple but effective instrument for instantaneous optical communication over long distances during the late 19th and early 20th century.[1] 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.[2]

Fig. 1: Signaling with a Mance heliograph, 1910


Heliograph (1)-2
Fig. 2: German heliograph made by R. Fuess in Berlin (on display at the Museum of Communication in Frankfurt)

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.[3] 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.[3] 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.[4][5] The U. S. Signal Corps heliograph mirror did not tilt. This type produced flashes by a shutter mounted on a second tripod (Fig 4).[4]

The heliograph had some great 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.[2][6] In the Boer War, where both sides used heliographs, tubes were sometimes used to decrease the dispersion of the beam.[2] 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.[7]

The distance that heliograph signals could be seen depended on the clarity of the sky and the size of the mirrors used. A clear line of sight was required, and since the Earth's surface is curved, the highest convenient points were used. Under ordinary conditions, a flash could be seen 30 miles (48 km) with the naked eye, and much farther with a telescope. The maximum range was considered to be 10 miles for each inch of mirror diameter. Mirrors ranged from 1.5 inches to 12 inches or more. The record distance was established by a detachment of U.S. signal sergeants by the inter-operation of stations on Mount Ellen, Utah, and Mount Uncompahgre, Colorado, 183 miles (295 km) apart on September 17, 1894, with Signal Corps heliographs carrying mirrors only 8 inches square.[8]


Turkish heliograph at Huj2
Fig. 3 Ottoman heliograph crew at Huj during World War I, 1917
Ruinen aus der Schutztruppen-Zeit Dicker Wilhelm
Ruins of German Schutztruppe on top of Dikwillem, where the Germans used to have a Heliographic Station (Bird's eye view 2017)

The German professor Carl Friedrich Gauss of the University of Göttingen developed and used a predecessor of the heliograph (the heliotrope) in 1821.[1][9] His device directed a controlled beam of sunlight to a distant station to be used as a marker for geodetic survey work, and was suggested as a means of telegraphic communications.[10] This is the first reliably documented heliographic device,[11] 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"[12] that the mainland signals Roman emperor Tiberius watched for from Capri[13] 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,[14] originating in the 1800s. Herodotus never mentioned any flash.[15] What Herodotus did write was that someone was accused of having arranged to "hold up a shield as a signal".[16] Suspicion grew in the 1900s that the flash theory was implausible.[17] The conclusion after testing the theory was "Nobody flashed a shield at the Battle of Marathon".[18]

In a letter dated 3 June 1778, John Norris, High Sheriff of Buckinghamshire, England, notes: "Did this day heliograph intelligence from Dr [Benjamin] Franklin in Paris to Wycombe".[19] However, there is little evidence that "heliograph" here is other than a misspelling of "holograph". The term "heliograph" for solar telegraphy did not enter the English language until the 1870s—even the word "telegraphy" was not coined until the 1790s.

Henry Christopher Mance (1840–1926), of the British Government Persian Gulf Telegraph Department, developed the first widely accepted heliograph about 1869[1][20][21] while stationed at Karachi, in the Bombay Presidency in British India. Mance was familiar with heliotropes by their use for the Great India Survey.[8] The Mance Heliograph was operated easily by one man, and since it weighed about seven pounds, the operator could readily carry the device and its tripod. The British Army tested the heliograph in India at a range of 35 miles with favorable results.[22] During the Jowaki Afridi expedition sent by the British-Indian government in 1877, the heliograph was first tested in war.[23][24]

Fig. 4: US Signal Service heliograph, 1898

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.[8]

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.[25][26][27] In 1886, General Nelson A. Miles set up a network of 27 heliograph stations in Arizona and New Mexico during the hunt for Geronimo[28].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.[29] 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.[8]

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.[30] In 1888, the US Signal Service reviewed all of these devices, as well as the Finley Helio-Telegraph,[30] and finding none completely suitable, developed the US Signal Service heliograph, a two-tripod, shutter-based machine of 13 7/8 lb. total weight, and ordered 100 for a total cost of $4,205.[31] In 1893, the number of heliographs manufactured for the US Signal Service was 133.[32]

The heyday of the heliograph was probably the Second Boer War in South Africa, where it was much used by both the British and the Boers.[1][2] 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 Aldis lamps, 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 garrisons were besieged in Kimberley, Ladysmith, and Mafeking. With land telegraph lines cut, the only contact with the outside world was via light-beam communication, helio by day, and Aldis lamps at night.[8]

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".[4] 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.[4]

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.[33] The Red Army during the Russian Civil War made use of a series of heliograph stations to disseminate intelligence efficiently about basmachi rebel movements in Turkestan in 1926.[34]

During World War II, South African and Australian forces used the heliograph against German forces in Libya and Egypt in 1941 and 1942.[1]

The heliograph remained standard equipment for military signallers in the Australian and British armies until the 1940s, where it was considered a "low probability of intercept" type of communication. The Canadian Army was the last major army to have the heliograph as an issue item. By the time the mirror instruments were retired, they were seldom used for signalling.[8] However, as recently as the 1980s, heliographs were used by Afghan forces during the Soviet invasion of Afghanistan.[1] Signal mirrors are still included in survival kits for emergency signaling to search and rescue aircraft.[1]

Automated heliographs

Most heliographs of the 19th and 20th century were completely manual.[4] 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 manual steps.[4] 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.[35] The Mangin apparatus with heliostat was still in service in 1917.[36][37][38] 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.[39] In 1961, the US Air Force was working on a space heliograph to signal between satellites[40]

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[41] where the public could schedule times for the mirrors to signal with sun-flashes, entering the time and their latitude, longitude and altitude.[42] The solar beacons were later moved to Sather Tower at UC Berkeley.[43][44] 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.[45] The designer described the Solar Beacon as a "heliostat", not a "heliograph".[42]

The first digitally controlled heliograph was designed and built in 2015.[46][47] It was a semi-finalist in the Broadcom MASTERS competition.[48]

See also


  1. ^ a b c d e f g h Woods, Daniel (2008). "Heliograph and Mirrors". In Sterling, Christopher. Military Communications: From Ancient Times to the 21st Century. ABC-CLIO. p. 208. ISBN 1851097325.
  2. ^ 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.
  3. ^ a b Signal Training. III. Pamphlet No. 2. Heliograph, 5-inch, Mark V. 1922. London: His Majesty's Stationery Office. 1922. pp. 10–13.
  4. ^ 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.
  5. ^ 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).
  6. ^ Kipling, Rudyard A Code of Morals. The Kipling Society website. Retrieved on 1 June 2008.
  7. ^ Signals, Royal. "The Heliograph". Signalling Handbook (1905). Retrieved 15 April 2012.
  8. ^ 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.
  9. ^ Dunnington, G. Waldo (2004). Carl Friedrich Gauss: Titan of Science. New York: The Mathematical Association of America. pp. 122–127. ISBN 0-88385-547-X.
  10. ^ "The Heliotrope". The Manchester Iris. 1 (32): 255–256. September 7, 1822. Retrieved 18 November 2012.
  11. ^ Holzmann, Gerard (1995). Björn Pehrson, ed. The early history of data networks. p. 10. ISBN 0818667826. Retrieved 18 November 2012.
  12. ^ 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.
  13. ^ Suetonius (1796). The Lives of the First Twelve Caesars. G.G. and J. Robinson, Paternoster-Row. p. 296.
  14. ^ Krentz, Peter (2010). The Battle of Marathon. Yale University. p. 160. ISBN 0300120850.
  15. ^ Sekunda, Nicholas (2002). Marathon 490 BC: The First Persian Invasion Of Greece. Osprey Publishing. p. 73. ISBN 1841760005.
  16. ^ 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.
  17. ^ Reynolds, P. K. Baillie (1929). "The Shield Signal at the Battle of Marathon". The Journal of Hellenic Studies. 49 (Part I). JSTOR 625005.
  18. ^ Hodge, A. Trevor (2001). "Reflections on the Shield at Marathon". The Annual of the British School at Athens. 96: 237–259. doi:10.1017/s0068245400005281. JSTOR 30073279.
  19. ^ Deacon, Richard (1978). The Silent War: a History of Western Naval Intelligence. David & Charles. p. 21. ISBN 978-0715375570.
  20. ^ Mance, Henry (10 February 1872). "The Heliograph or Sun Telegraph". United Service Institution of India. 1 (5): 123–130. Retrieved 16 June 2013.
  21. ^ Goode, Samuel (June 14, 1875). "Mance's Heliograph, or Sun-Telegraph". Journal of the Royal United Service Institution. XIX (LXXXIII): 534–548. doi:10.1080/03071847509415772. Retrieved 2011-06-21.
  22. ^ Luck, George (1872-05-24). "Army Signalling, Heliograph". United Service Institution of India. 2 (7): 101–105.
  23. ^ Wynne, Major A.S. (March 15, 1880). "Heliography and Army Signalling Generally". Journal of the Royal United Service Institution. XXIV (CV): 235–258. doi:10.1080/03071848009417153. Retrieved June 21, 2011.
  24. ^ 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.
  25. ^ Steinbach, Robert (1989). The Lives of Frank and Alice Baldwin (1 ed.). Austin: University of Texas Press. p. 136. ISBN 0-292-74659-8.
  26. ^ Reade, Lt. Philip (January 1880). "About Heliographs". The United Service. 2: 91–108. Retrieved June 21, 2011.
  27. ^ "The Pacific Slope". Daily Alta California. 37 (12578): 5. 20 September 1884.
  28. ^ 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.
  29. ^ Greely, Adolphus (August 1899). "The Evolution of the Signal Corps". Ainslee's Magazine. IV (1): 17. Retrieved 31 March 2017.
  30. ^ 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.
  31. ^ Annual Report of the Chief Signal Officer of the Army to the Secretary of War, Google Books, 1889, pp. 43–7, retrieved 3 June 2008.
  32. ^ Report of the Chief Signal Officer. U.S. G.P.O. 1893. p. 671.
  33. ^ Littauer, Vladimir. Russian Hussar. p. 123. ISBN 1-59048-256-5.
  34. ^ Everett-Heath, Tom, Central Asia: Aspects of Transition, p. 20, retrieved 3 June 2008.
  35. ^ Ternant, A.-L. (1884). Les télégraphes (2nd ed.). Hachette. pp. 35–65.
  36. ^ 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.
  37. ^ BOUCHETHAL, J.L. (1916). "LA TÉLÉGRAPHIE OPTIQUE AUX ARMÉES". La Science et La Vie (28): 337–342.
  38. ^ "Ottoman Soldiers Mounting Signal Apparatus, 1917". Flickr. Ottoman Imperial Archives. Retrieved 7 September 2015.
  39. ^ "The Heliograph in Mauritius". Engineering. 34: 363. October 13, 1882.
  40. ^ Pursglove, S. David (1961). "Ancient Heliograph Goes Modern for Space Age". Science and Mechanics: 70. Archived from the original on May 25, 2011.
  41. ^ "Solar Beacon". Archived from the original on 30 May 2012. Retrieved 30 May 2012.
  42. ^ a b Boxall, Bettina. "Golden Gate Bridge is prepared for 75th birthday celebration". LA Now. Los Angeles Times.
  43. ^ Tuan, Lydia (10 September 2013). "Solar Beacon atop Campanile allows for safe observation of sunlight". The Daily Californian.
  44. ^ "Solar Beacon". Retrieved 7 September 2015.
  45. ^ Vallerga, John. "Custom Show Setting". Solar Beacon. Retrieved 28 June 2012.
  46. ^ "IPA Freshman's science fair project". Island Pacific Academy. Retrieved 6 September 2015.
  47. ^ Welch, Natalie. "Digital Heliograph". Retrieved 6 September 2015.
  48. ^ "2015 Broadcom MASTERS Semifinalists". Retrieved 5 September 2015.

Further reading

  • Lewis Coe, Great Days of the Heliograph, Crown Point, 1987 OCLC 16902284

External links

Erigeron heliographis

Erigeron heliographis is a rare species of flowering plant in the aster family known by the common name Heliograph Peak fleabane. It is endemic to Arizona, where it occurs only in the Pinaleno Mountains in Graham County.This perennial herb grows a few centimeters tall from a taproot and caudex. The rough-haired leaves are linear or lance-shaped and 1 to 4 centimeters long. The flower head contains 20 to 23 white ray florets 5 to 8 millimeters long.This plant is known from two peaks in the Pinaleno Mountains of Arizona. It occurs at an elevation between 8500 and 10,400 feet, growing in rocky, forested habitat.

Forgotten Futures

Forgotten Futures is a role-playing game created by Marcus Rowland to allow people to play in settings inspired by Victorian and Edwardian science fiction and fantasy (i.e., steampunk). Most of its releases begin with these stories then add background material to explain the settings (often as alternate worlds, whose history diverges from our own), adventures, and other game material.

Gauribidanur Radio Observatory

The Gauribidanur Radio Observatory is a radio telescope observatory located at Gauribidanur, near Bengaluru. It is operated jointly by Raman Research Institute and the Indian Institute of Astrophysics. The observatory has been in operation since 1976.

Harquahala Mountains

The Harquahala Mountains (Yavapai: ʼHakhe:la) are the highest mountain range in southwestern Arizona, United States and are located southwest of the towns of Aguila and Wenden. The name originated from the Yavapai 'ʼHakhe:la", which means "running water". The range is oriented from northeast to southwest and is approximately 32 km long and 20 km at its widest point. At the northeast are two prominent peaks, Eagle Eye Peak and Eagle Eye Mountain. One has a natural opening or bridge through it appearing as an eye high up, and is the namesake for the peaks and Aguila (Spanish for eagle). The highest point, Harquahala Peak, rises to 5,681 ft (1,732 m). Socorro Peak, 3270 ft (1,134 m), is at the southwest end of the range.

The very windy summit can be reached via a rough, 4-wheel drive road. This high point was used by the U.S. Army in the 1880s as a heliograph station. Then in 1920 a Smithsonian Astrophysical Observatory was constructed on this summit and operated for five years before being relocated to Table Mountain Observatory, near Wrightwood, California. Its purpose was to study variations in the solar output as a possible factor in climate prediction.

Designated in 1990, the 22,880-acre (93 km2) the Harquahala Mountain Wilderness lies to the north and east of the summit at 33°49′40″N 113°17′52″W on the Maricopa / La Paz county line.

At the southwest end of the mountain range, there are gypsum mines and in the past there were extensive mines for gold and silver.

Heliograph (disambiguation)

Heliograph is a word derived from helios (Greek Ἥλιος / ἥλιος "sun") and graphein (γραφειν "to write"). It has several uses:

the heliograph, a device used for optical signalling

a type of sunshine recorder

a solar telescope, a telescope especially adapted for viewing the surface of the sun

heliography, the photographic process used to make the earliest known permanent photograph from nature


Heliography (in French, héliographie) is the photographic process invented by Joseph Nicéphore Niépce around 1822, which he used to make the earliest known surviving photograph from nature, View from the Window at Le Gras (1826 or 1827). The process used Bitumen of Judea, a naturally occurring asphalt, as a coating on glass or metal. It hardened in proportion to its exposure to light. When the plate was washed with oil of lavender, only the hardened areas remained.

The word has also been used to refer to other phenomena: for description of the sun (cf. geography), for photography in general, for signalling by heliograph (a device less commonly called a heliotrope or helio-telegraph), and for photography of the sun.The abbreviations héliog. or héliogr., found on old reproductions, may stand for the French word héliogravure, and can then refer to any form of photogravure.

Henry Christopher Mance

Sir Henry Christopher Mance, (6 September 1840 – 21 April 1926) was a British electrical engineer who was president of the Institution of Electrical Engineers. He was knighted for developing the heliograph.Born in Exeter, he was educated privately.

He joined the Persian Gulf Telegraph Department in 1863, and was employed on the laying of the first Persian Gulf submarine communications cable. In 1879, he was appointed electrician to the Department, which position he held throughout his working life. An inventive man, he was responsible for a number of important developments in the field of cable laying, testing and usage.

In 1869 he invented the heliograph, a wireless solar telegraph that signals by flashes of sunlight using Morse code reflected by a mirror. The flashes were produced by momentarily pivoting the mirror. Frustrated by Government lack of interest, he sent a number of his instruments to Lord Roberts for use during the second Afghan War, where the practical value of the invention was realised. It was subsequently adopted by military services worldwide and was still being used in World War II.

He was Vice-President of the Institution of Electrical Engineers from 1892 to 1896 and elected President in 1897. He was also a member of the Institution of Civil Engineers and the Physical Society.

He retired in 1885 but continued his interest in Electrical Engineering as Chairman of the Oxford Electric Company and board member of several other electrical companies. Practically blind for the last 10 years of his life, he learned to read Braille.

He was created a C.I.E. in 1883 and made a Knight Bachelor in 1885.He died in 1926. He had married Annie Sayer in 1874, and had three sons and two daughters. One son was Brigadier-General Henry Osborne Mance.

List of peaks named Signal

A signal mountain or signal peak is a mountain suited to sending and receiving visual signals, either from its topographic prominence and isolation or from being located where signal communications are most needed. For example, Tennessee's Signal Mountain was used by Native Americans to send fire and smoke signals across the Tennessee Valley. It was also used by the Union Army as a visual communications station during the American Civil War. Mount Lassic in California has low prominence but is also known as Signal Peak due to the heliograph station that was located on this peak around 1900. And the highest peak in the Pine Valley Range, Utah's Signal Peak, is "supposedly named because of its use in World War II when beacons were placed on the mountain to guide airplanes at night."

Marcus Rowland (author)

Marcus L. Rowland (born 1953) is an English retired laboratory technician and an important figure in gaming, particularly with regard to games with Victorian era content.

Morse Code (horse)

Morse Code (foaled 1929) was a British Thoroughbred racehorse who won the 1938 Cheltenham Gold Cup. His Gold Cup victory was achieved at the expense of Golden Miller, who was attempting to win the race for the sixth time. He had previously won the Grand Annual Chase and went on to finish second when odds-on favourite for the Gold Cup in 1939.

Mount Ellen (Utah)

Mount Ellen is a mountain located in Garfield County, Utah. The high point of Mount Ellen's North Summit Ridge is the highest point in the Henry Mountains; it is also the highest point in Garfield County. It can be reached by a short hike from an unpaved road. These mountains were the last to be surveyed by the USGS in the lower 48 states. The mountain can be seen from as far as Mount Peale in the La Sal Mountains of eastern Utah.

Mount Ellen is an ultra prominent peak, meaning that it has more than 1,500 metres (4,921 ft) of topographic prominence, standing out considerably from nearby mountains. It stands in the watershed of the Fremont River, which together with Muddy Creek forms the Dirty Devil River, which drains into the Colorado River, and ultimately into the Gulf of California in Mexico.

The Paiute name for Mount Ellen was Un tar re. It was also referred to as First Mountain. After climbing to the summit in June 1872, Almon Harris Thompson named it for his wife Ellen. Ellen Powell Thompson was also the sister of explorer John Wesley Powell.Over several days beginning on September 10th, 1895 a detachment of the U.S. Army Signal Corps established the world heliograph record from stations atop Mount Ellen, Utah and Mount Uncompahgre, Colorado. The record for visual signalling was established utilizing mirrors 8 inches across and telescopes. The flashing signals communicated over a distance of 183 miles.

Nançay Radio Observatory

The Nançay Radio Observatory or Nançay Radioastronomy Facility' includes a number of radio telescopes:

The Nançay radio telescope

the Radio Heliograph, a T-shaped array (1.6 km by 1.25 km) composed of 47 antennas operating between frequencies of 150 and 450 MHz;

the Decametric Array composed of 144 spiral antenna operating between wavelengths of 3 m and 30 m;

the Radio Frequency Monitoring Antenna, mounted on a tower 22 metres above the ground, and observing at regular intervals each day on two frequency bands between 100 and 500 MHz and between 1 and 4 GHz.

the CODALEMA project, dedicated to the study of cosmic rays;

an international LOFAR station (named FR606), along with NenuFAR - a LOFAR Super Station with an extended low frequency range, capable of also operating in standalone mode;

one of the two experimental EMBRACE (Electronic MultiBeam Radio Astronomy ConcEpt) phased array telescopes, part of the Research and Development program for the Phase 2 of the Square Kilometre Array (SKA) project.

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 back several millennia, while the earliest electrical device created to do so was the photophone, invented in 1880.

An optical communication system uses a transmitter, which encodes a message into an optical signal, a channel, which carries the signal to its destination, and a receiver, which reproduces the message from the received optical signal. When electronic equipment is not employed the 'receiver' is a person visually observing and interpreting a signal, which may be either simple (such as the presence of a beacon fire) or complex (such as lights using color codes or flashed in a Morse code sequence).

Free-space optical communication has been deployed in space, while terrestrial forms are naturally limited by geography, weather and the availability of light. This article provides a basic introduction to different forms of optical communication.

Pinaleño Mountains

The Pinaleño Mountains (in Yavapai: Walkame – "pine mountains" or in Western Apache: Dził Nnilchí' Diyiléé - ″pine-burdened mountain″), are a remote mountain range in southeastern Arizona, near Safford (Ichʼįʼ Nahiłtį́į́), Arizona. The mountains have over 7,000 feet (2,100 m) of vertical relief, more than any other range in the state. The mountains are surrounded by the Sonoran-Chihuahuan Desert. Subalpine forests cover the higher elevations. According to The Nature Conservancy, they traverse five ecological communities and contain "the highest diversity of habitats of any mountain range in North America." The highest point is Mount Graham (Western Apache: Dził Nchaa Sí'an - ″Big Seated Mountain″) at 10,720 feet (3,267 m). Locals often refer to the whole mountain range as "Mount Graham", in which case the peak is referred to as "High Peak". The mountains cover 300 square miles (780 km2) and are part of the Coronado National Forest, Safford ranger district.

The Pinaleño/Pinal Band (Spanish term: ″Pinery People″, Western Apache: Tiis Ebah Nnee - ″Cottonwoods Gray in the Rocks People″) of the San Carlos Apache (Tsékʼáádn - ″Metate People″), one of the subgroups of the Western Apache people and their kin and close allies, the Hwaalkamvepaya/Walkamepa Band ("Pine Mountains People") of the Guwevkabaya/Kwevkepaya ("Southern People"), one of the three Yavapai regional groupings were either named after the Pinaleño Mountains or the mountains were named after them (both people used this range as primary source for pine nuts, which have long been a staple food for many Native American tribes).

The mountains are a Madrean sky island range that is typical of southern Arizona, specifically south-central Arizona, and especially the complete southeastern quadrant of Arizona, from Tucson, and Globe to Nogales, Douglas, and the Chiricahuas. Sky island ranges are mountains isolated by desert valleys. The deserts, as well as differences in elevation, prevent flora and fauna from traveling to or from nearby ecosystems. As a result, the mountain ecosystems are isolated, and distinct sub-species can develop. This is similar to what Charles Darwin discovered with species he collected from different islands in the Galápagos, a discovery that played a major role in his theory of natural selection. The Mount Graham red squirrel is an isolated population of red squirrels and possibly a sub-species as well.

Safford and Willcox, Arizona are the nearest towns to the Pinaleños.

Solar telescope

A solar telescope is a special purpose telescope used to observe the Sun. Solar telescopes usually detect light with wavelengths in, or not far outside, the visible spectrum. Obsolete names for Sun telescopes include heliograph and photoheliograph.

Sunshine recorder

A sunshine recorder is a device that records the amount of sunshine at a given location or region at any time. The results provide information about the weather and climate as well as the temperature of a geographical area. This information is useful in meteorology, science, agriculture, tourism, and other fields. It has also been called a heliograph.

There are two basic types of sunshine recorders. One type uses the sun itself as a time-scale for the sunshine readings. The other type uses some form of clock for the time scale.

Older recorders required a human observer to interpret the results; recorded results might differ among observers. Modern sunshine recorders use electronics and computers for precise data that do not depend on a human interpreter. Newer recorders can also measure the global and diffuse radiation.


Telegraphy is the long-distance transmission of textual 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 pigeon post is not. Ancient signalling systems, although sometimes quite extensive and sophisticated as in China, were generally not capable of transmitting arbitrary text messages. Possible messages were fixed and predetermined and such systems are thus not true telegraphs.

The earliest true telegraph put into widespread use was the optical telegraph of Claude Chappe, invented in the late eighteenth century. The system was extensively used in France, and European countries controlled by France, during the Napoleonic era. The electric telegraph started to replace the optical telegraph in the mid-nineteenth century. It was first taken up in Britain in the form of the Cooke and Wheatstone telegraph, initally used mostly as an aid to railway signalling. This was quickly followed by a different system developed in the United States by Samuel Morse. The electric telegraph was slower to develop in France due to the established optical telegraph system, but an electrical telegraph was put into use with a code compatible with the Chappe optical telegraph. The Morse system was adopted as the international standard in 1865, using a modified Morse code developed in Germany.

The heliograph is a telegraph system using reflected sunlight for signalling. It was mainly used in areas where the electrical telegraph had not been established and generally uses the same code. The most extensive heliograph network established was in Arizona and New Mexico during the Apache Wars. The heliograph was standard military equipment as late as World War II. Wireless telegraphy developed in the early twentieth century. Wireless telegraphy became important for maritime use, and was a competitor to electrical telegraphy using submarine telegraph cables in international communications.

Telegrams became a popular means of sending messages once telegraph prices had fallen sufficiently. Traffic was became high enough to spur the development of automated systems – teleprinters and punched tape transmission. These systems led to new telegraph codes, starting with the Baudot code. However, telegrams were never able to compete with the letter post on price, and competition from the telephone, which removed their speed advantage, drove the telegraph into decline from 1920 onwards. The few remaining telegraph applications were largely taken over by alternatives on the internet towards the end of the twenty-first century.

Warrior Princess

Warrior Princess may refer to:

"Warrior Princess", the 2014 Mongolian hit film about the life of Queen Anu

Xena: Warrior Princess, a 1995-2001 American television series

"The Warrior Princess" (Hercules: The Legendary Journeys), an episode of Hercules: The Legendary Journeys

Xena: Warrior Princess (comics)

X-wing Rogue Squadron: The Warrior Princess, a 1996 story arc of the X-wing: Rogue Squadron comics series

Diana: Warrior Princess, a 2003 roleplaying game by Heliograph Incorporated

Warrior Princess: A U.S. Navy SEAL's Journey to Coming out Transgender, a 2013 memoir of Kristin Beck, a former United States Navy SEAL who came out as a trans woman

nickname of English professional kickboxer Ruqsana Begum (born 1983)

Transmission methods
Notable signals
Other writing systems
in Morse code

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