a special lens 10 feet long for his camera which was set up in a bunker 7 miles from the source of the blast which was triggered Nevada - the bomb placed atop a steel gantry anchored to the desert floor by guide wires. The exposures are at 1/100,000,000ths of a second.

Automatic Camera situated 7 miles from blast with 10 foot lens. Shutter speed equaled 1/100,000,000 of-a-second exposure.
With energy so great, the electric like energy runs down the towers guide wires and turning the desert floor to glass.
With a planet of fire, Joshua tree's near the base get vaporized in just microseconds.
Courtesy of Harold Edgerton, da photographer