K for Klieglight

A Klieg light is an intense carbon arc lamp especially used in filmmaking.

It is named after inventor John Kliegl and his brother Anton Kliegl. They usually have a Fresnel lens with a spherical reflector or an ellipsoidal reflector with a lens train containing two plano-convex lenses or a single step lens. And if you understood all that, you already know what kind of lamp this is.

When introduced in the 1920’s the two carbon rods burnt so brightly, they would have to be replaced every two hours. 

The modern versions use xenon or mercury and argon to produce light.

The light is so intense, it can be seen from up to 35 miles away.

Lights with 1.4 billion candlepower have been used to communicate with the International Space Station, announce movie premieres, and (of course) to signal for Batman!