Searchlight

A searchlight (or spotlight) is an apparatus that combines an extremely 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.

[1] However, Rare-earth elements such as lanthanum (La) and cerium (Ce) are used in phosphors to improve light quality in some specialized searchlights.

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.

[5] Searchlights were installed on most naval capital ships from the late 19th century through WWII, both for tracking small, close-in targets such as torpedo boats, and for engaging enemy units in nighttime gun battles.

Controlled by sound locators and radars, searchlights could track bombers, indicating targets to anti-aircraft guns and night fighters and dazzling crews.

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.

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 bombs and depth charges.

Their use was once common for movie premieres; the waving searchlight beams can still be seen as a design element in the logos of 20th Century Studios and the Fox television network.

Tribute in Light is an art installation that uses two columns of searchlights to represent the former Twin Towers of the World Trade Center, in remembrance of the September 11 attacks.