Jack W. Aeby (/ˈæbi/; born August 16, 1923) is an Americanenvironmental physicist most famous for having taken the only well-exposed color photograph of the first detonation of a nuclear weapon on July 16, 1945 at the Trinity nuclear test site in New Mexico. While color motion pictures of the Trinity test were made, most were badly overexposed or damaged due to the fireball's tendency to blister and solarize the film. Aeby was a civilian assigned to the Health Physics Group with Emilio Segrè at the time his snapshot was taken.
Aeby is a source for a story about a notable estimate made by Enrico Fermi at that test:
As the shock wave hit Base Camp, Aeby saw Enrico Fermi with a handful of torn paper. "He was dribbling it in the air. When the shock wave came it moved the confetti. He thought for a moment."
Fermi had just estimated the yield of the first nuclear explosion. It was in the ball park.[dead link]
Fermi's strips-of paper estimate was ten kilotons of TNT; the actual yield was about 19 kilotons.[unreliable source?]