Searchlight

From Wikipedia, the free encyclopedia

For other uses of searchlight see Searchlight (disambiguation).

A searchlight is an apparatus with reflectors for projecting a powerful beam of light of approximately parallel rays in a particular direction, usually devised so that it can be swiveled about.

Searchlights were first used in World War I to create "artificial moonlight" to enhance opportunities for night attacks, a practice which continued in World War II. Artificial moonlight was invented by historian and tank warfare theorist, Gen. J.F.C. Fuller.

Searchlights were used extensively in defence against nighttime aerial bomber raids around the time of World War II. In particular, pairs of searchlights spaced a known distance apart were used to determine (via triangulation) the altitude of enemy bombers, so that the fuses on anti-aircraft flak shells could be set appropriately for maximum effect. In addition, the lights may have helped blind bombardiers using optical bombsights.

Searchlights were occasionally used tactically in ground battles. One famous occasion was the Soviet's use of seachlights during the Battle of Berlin in April 1945. 143 searchlights, aimed to blind Nazi General Henrici's defense force across the Neisse River, failed as the morning fog diffused the light and made silhouettes of the attacking Soviet 1BF. The deeply entrenched Nazi army, muddy terrain, and spotlight mishap combined to cause large Soviet losses and a delayed penetration of the city.

World War II searchlights include the General Electric 1942-A Searchlight. This was a 60" (152.4 cm) in diameter lamp producing 800,000,000 candela. It ran off a 15 KW generator and had an effective beam visibility of 28 to 35 miles (45 to 56 km). [1]. UK hire company Fineline[2], currently has the largest stock of original World War II searchlights in working order, some of which have been converted from the original carbon arc system to a more modern xenon arc lamp technology.

More recently, searchlights are often used in advertising[3], for instance by automobile dealers; the beam of light is visible over a large area, and (at least in theory) interested persons can find the dealer or store by following the beam to its source. This also used to be done for movie premieres; the waving searchlight beams are still to be seen as a design element in the logo of the 20th Century Fox movie studio. Some of the searchlights used today in the advertising and event industry include Syncrolites and Diablo [4], the latter can be controlled via radio link and is fully automated.

Sources

• http://www.geocities.com/bobz299/searchlight.htm
• http://www.ftmac.org/SperryLight.htm
• http://www.peakbeam.com
• http://www.fineline.uk.com

See also

• Military applications of searchlight
  • Canal Defence Light
  • Leigh light