Editing Searchlight

{{Short description|Intense focused beam lamp for improving visual detection}}
{{Other uses|Searchlight (disambiguation)}}

[[File:The Auxiliary Territorial Service in the United Kingdom 1939 - 1945 H36315.jpg|thumb|[[Auxiliary Territorial Service|ATS]] officers-in-training crew a 90 cm searchlight in Western Command, 1944]]

A '''searchlight''' (or '''spotlight''') is an apparatus that combines an extremely [[luminosity|bright]] source (traditionally a [[carbon arc lamp]]) with a mirrored [[parabolic reflector]] to project a powerful beam of [[light]] of approximately parallel rays in a particular direction. It is usually constructed so that it can be swiveled about. The most common element used in modern searchlights is [[Xenon|Xenon (Xe)]].<ref>{{cite journal |last=Rehmet |first=M. |year=1980 |title=Xenon lamps |journal=IEE Proceedings A - Physical Science, Measurement and Instrumentation, Management and Education, Reviews |volume=127 |issue=3 |pages=190–195 |doi=10.1049/ip-a-1.1980.0030 |issn=0143-702X}}</ref> However, [[Rare-earth elements]] such as [[lanthanum|lanthanum (La)]] and [[cerium|cerium (Ce)]] are used in [[phosphors]] to improve light quality in some specialized searchlights.<ref>{{cite web |url=https://www.stanfordmaterials.com/blog/lanthanide.html |title=What Are the Lanthanide Series? |last=Lowen |first=Eric |website=Stanford Advanced Materials |access-date=Sep 9, 2024}}</ref>

== Military use ==
[[File:Attaque nocturne.jpg|thumb|right|Russian troops use a searchlight against a Japanese night attack during the [[Russo-Japanese War]], 1904]]
[[File:Task Force Guardian - Flickr - The National Guard (1).jpg|thumb|left|Homeland Security helicopter utilizing its searchlight.]]

The first use of searchlights using carbon arc technology occurred during the [[Siege of Paris (1870-71)|Siege of Paris]] during the [[Franco-Prussian War]].<ref>{{cite book |last = Stirling |first = Christopher |title = Military Communications From Ancient Times to the 21st Century |edition = 1st |year = 2008 |publisher = ABC-CLIO |location = Santa Barbara, CA |isbn = 978-1-85109-732-6 |page = 395 }}</ref> The [[Royal Navy]] used searchlights in 1882 to dazzle and prevent Egyptian forces from manning artillery batteries at [[Bombardment of Alexandria|Alexandria]]. Later that same year, the French and British forces landed troops under searchlights.<ref>{{cite book |last = Sterling |first = Christopher H. |title = Military Communications |year = 2008 |publisher = ABC-CLIO |pages = 395–396 |isbn = 978-1-85109-732-6 }}</ref>

By 1907 the value of searchlights had become widely recognized. One recent use was to assist attacks by [[torpedo boat]]s by dazzling gun crews on the ships being attacked. Other uses included detecting enemy ships at greater distances, as signaling devices, and to assist landing parties. Searchlights were also used by battleships and other capital vessels to locate attacking torpedo boats and were installed on many coastal artillery batteries for aiding night combat. They saw use in the [[Russo-Japanese War]] from 1904–05.<ref>{{cite book | last = Barry | first = Richard | title = Port Arthur: A Monster Heroism | publisher = Moffat, Yard & Co. | year = 1905 | pages = 324–325 }}</ref>

Searchlights were installed on most naval [[capital ship]]s from the late 19th century through [[World War II|WWII]], both for tracking small, close-in targets such as [[torpedo boat]]s, and for engaging enemy units in nighttime gun battles. The [[Imperial Japanese Navy]] especially was known for its intensive development of nighttime [[Naval tactics|naval combat tactics]] and extensive training. The [[Pacific War|War in the Pacific]] saw a number of nocturnal engagements fought by searchlight, particularly the [[Naval Battle of Guadalcanal|Battle of Savo Sound]] at Guadalcanal. Although searchlights remained in use throughout the war, the newly developed [[radar]] proved to be a far more effective locating device, and Japanese radar development lagged far behind that of the US.

=== First World War ===
[[File:American searchlight crew and equipment in action on Somme front, WWI (32689502005).jpg|right|thumb|American searchlight crew and equipment in France during WWI]]
Searchlights were first used in the [[World War I|First World War]] to create "artificial moonlight" to enhance opportunities for night attacks by reflecting searchlight beams off the bottoms of clouds, a practice which continued in the [[World War II|Second World War]]. The term "artificial moonlight" was used to distinguish illumination provided by searchlights from that provided by natural moonlight, which was referred to as "movement light" in night-time manoeuvers.<ref>{{cite journal | title = Artificial Moonlight | journal = Tactical and Technical Trends | issue = 57 | publisher = US Army Military Intelligence Corps | date = April 1945 }}</ref> Searchlights were also heavily used in the defense of the UK against [[German strategic bombing during World War I|German nighttime bombing raids]] using [[Zeppelins]].

=== Second World War ===
Searchlights were used extensively in defense against nighttime [[bomber]] raids during the [[World War II|Second World War]]. Controlled by sound locators and radars, searchlights could track bombers, indicating targets to anti-aircraft guns and night fighters and dazzling crews.

[[File:Searchlights pierce the night sky during an air-raid practice on Gibraltar, 20 November 1942. GM1852.jpg|thumb|right|Searchlights pierce the night sky during an air-raid practice on Gibraltar, 1942]]
Searchlights were occasionally used tactically in ground battles. One notable occasion was the [[Red Army]] use of searchlights during the [[Battle of the Seelow Heights]] in April 1945. 143 searchlights were directed at the German defence force, with the aim of temporarily blinding them during a Soviet offensive, begun with the largest artillery bombardment the world had ever seen until that point. However, the morning fog diffused the light and silhouetted the attacking Soviet forces, making them clearly visible to the Germans. The Soviets suffered heavy losses as a result and were forced to delay their invasion of the city.<ref>{{cite web |url = https://warfarehistorynetwork.com/daily/wwii/masterful-defense-at-seelow-heights/ |title = Masterful Defense at Seelow Heights |last = Welsh |first = William E. |date = June 2017 |website = Warfare History Network |access-date = 2018-09-18 |archive-date = 2016-09-16 |archive-url = https://web.archive.org/web/20160916133819/https://warfarehistorynetwork.com/daily/wwii/masterful-defense-at-seelow-heights/ |url-status = dead }}</ref>

[[File:British Eighth Army Troops Crossing the River Po, Beyond Ferrara, Italy, 28 April 1945 TR2854.jpg|thumb|right|upright|Members of a [[Royal Artillery]], anti-aircraft searchlight detachment clean the mirror of their searchlight, Italy, April 1945]]

Second World War-era searchlights include models manufactured by [[General Electric]] and by the [[Sperry Corporation|Sperry Company]]. These were mostly of 60 inch (152.4&nbsp;cm) diameter with [[rhodium]] plated parabolic mirror, reflecting a [[Arc lamp|carbon arc]] discharge. Peak output was 800,000,000 [[candela]]. It was powered by a 15&nbsp;kW generator and had an effective beam visibility of 28 to 35 miles (45 to 56&nbsp;km) in clear low humidity.

The searchlight also found a niche for use by [[night fighter]]s and [[anti-submarine warfare]] aircraft. The [[Turbinlite]] was a powerful searchlight mounted in the nose of an [[Royal Air Force|RAF]] [[Douglas A-20 Havoc|Douglas Boston]] [[light bomber]], converted into a night fighter to shoot down [[Luftwaffe]] night [[bomber]]s. The aircraft would be directed in the general direction of the enemy by ground-based or [[Radar in World War II|metre-wave]] airborne radar, and the pilot would then switch on the Turbinlite, illuminating the enemy aircraft, which would then be shot down by accompanying RAF [[day fighter]]s such as the [[Hawker Hurricane]]. This never proved very successful, as the light made the emitting aircraft a very big target for rear gunners, who would simply have to shoot into the light and be guaranteed to hit something eventually.

During the [[Battle of the Atlantic|Battle of the North Atlantic]], RAF aircraft such as the [[Vickers Wellington]] were assigned to patrol for surfaced German [[U-boat]]s at night, when they would be on the surface, charging their [[Battery (electricity)|batteries]]. A large searchlight called a [[Leigh light]] was suspended from the bottom of the [[wing]] or [[fuselage]], and would be used to illuminate the surfaced U-boat while it was being attacked with [[bomb]]s and [[depth charge]]s. The Leigh light was somewhat more successful than the Turbinlite, but in both cases the development of centimeter-wave radar proved to be the far more effective answer.

=== War in Ukraine ===
During the [[2022 Russian invasion of Ukraine]], both the [[Russian Armed Forces]] and [[Territorial Defence Forces (Ukraine)]] have extensively used spotlights for both [[Civil defense]] purposes, aswell as frontline anti-drone and [[anti-aircraft warfare]].<ref>{{cite tweet |number=1609675916149489664 |user=Osinttechnical |title=https://t.co/r4jYvnd3Qf |author=OSINTtechnical |date=1 January 2023 |access-date=10 February 2023 |archive-url=https://web.archive.org/web/20230103022558/https://twitter.com/osinttechnical/status/1609675916149489664 |archive-date=3 January 2023 |url-status=live}}</ref>
[[File:Spotlight_from_Drone.png|thumb|Spotlights captured from a camera mounted to a "Geranium-2" Loitering Muntion over Kropyvnytskyi, January 5th 2025]]

== Non-military use ==
Today, searchlights are used in [[advertising]], [[fairs]], [[festivals]] and other public events. Their use was once common for [[film|movie]] [[premiere]]s; the waving searchlight beams can still be seen as a design element in the logos of [[20th Century Studios]] and the [[Fox Broadcasting Company|Fox television network]]. The world's most powerful searchlight today beams from the top of the pyramid-shaped [[Luxor Las Vegas|Luxor Hotel]] in [[Las Vegas]]. It concentrates about 13,650,000 [[Lumen (unit)|lumens]] from 39 7kW [[Xenon arc lamp|xenon lamps]] into a beam of about 9,129,000,000 [[candela]].

''[[Tribute in Light]]'' is an art installation that uses two columns of searchlights to represent the former [[World Trade Center (1973–2001)|Twin Towers of the World Trade Center]], in remembrance of the [[September 11 attacks]]. It is produced annually in [[Lower Manhattan]].

Disney parks uses searchlights in their nighttime fireworks displays. They are installed on top of the rooftops of several attractions in [[Fantasyland]].

<gallery mode="packed" heights="200px">
File:Searchlights at the W at Bonifacio High Street, Manila.JPG|Searchlights at [[New Year's Eve]] 2012 in Bonifacio Global City, Philippines
File:LuminatoatHarbourfront.jpg|Use of searchlights at the [[Luminato]] arts festival in Toronto
File:Tokyo sky tree23.jpg|Searchlights demonstrating the height of [[Tokyo Skytree]] before its construction in 2007
File:Light beam, Luxor, Las Vegas (6433695339).jpg|[[Luxor Sky Beam]]
File:September_11th_Memorial_Tribute_In_Light_2014.jpg|[[Tribute in Light]], representing the World Trade Center twin towers in remembrance of the September 11 attacks
File:20th Century-Fox fanfare 1947.webm|Animated searchlights are a part of the distinctive [[production logo]] used at the start of [[20th Century Fox]] films since the 1930s
File:KLJB 2016 logo.png|A logo for [[Fox Broadcasting Company|Fox]] affiliate [[KLJB]], one of many examples of a Fox station still using searchlights in their logo.
</gallery>

== See also ==
* [[Mangin mirror]]
* [[Cathedral of light]]
* ''[[Tribute in Light]]''
* Military applications of searchlight
** [[Canal Defence Light]]
** [[Turbinlite]]
** [[Leigh light]]
** [[G-numbers]]
** [[German searchlights of World War II]]

== References ==
=== Citations ===
{{Reflist}}

=== Sources ===
{{refbegin}}
* FM 4-29 seacoast searchlights
* [http://www.ibiblio.org/hyperwar/USA/ref/FM/PDFs/FM4-111.PDF FM 4-111] {{Webarchive|url=https://web.archive.org/web/20101227131145/http://ibiblio.org/hyperwar/USA/ref/FM/PDFs/FM4-111.PDF |date=2010-12-27 }} Coast Artillery Field Manual, Antiaircraft Artillery, Position Finding and Control, Antiaircraft Search-lights (US War Department, 1940)
* FM 4-115
{{refend}}

== External links ==
{{Commons category|Searchlights}}
* [http://www.ftmac.org/SperryLight.htm Sperry searchlight restoration project]
* [http://www.skylighters.org/howalightworks/index.html How Were World War II Searchlights Used?] {{Webarchive|url=https://web.archive.org/web/20210125002826/http://www.skylighters.org/howalightworks/index.html |date=2021-01-25 }} Information on a website commemorating the US 225th AAA Searchlight Battalion
* [https://books.google.com/books?id=ySUDAAAAMBAJ&pg=PA49 "Giant Lights Paint The Sky To Work New Magic"] July ''Popular Mechanics''—i.e. early article on one of the first commercial use of searchlights.
* director restored [http://www.ftmac.org/DEC_Project.htm]
* [http://www.lonesentry.com/articles/ttt07/searchlights.html German Searchlights], a 1943 article from the U.S. War Dept.

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{{Artificial light sources}}

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[[Category:Searchlights| ]]
[[Category:Types of lamp]]
[[Category:Articles containing video clips]]