Jack W. Aeby (/ˈæbi/; August 16, 1923-June 19, 2015) was an American environmental 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."

Fermi had just estimated the yield of the first nuclear explosion at the equivalent of 10,000 tons of TNT. Later measures put the yield nearly twice as much, at 18.6 kilotons. And this terrible new energy came from a plutonium ball weighing 13.6 pounds.

The photo was taken with a Perfex 33 with a 35mm lens, using a shutter speed of 1/100 at f4 and Anscochrome color film.

Aeby joined the Manhattan Project in 1942 and through his work with the Los Alamos National Laboratory witnessed nearly 100 nuclear explosions. He currently lives in the Española Valley innorthern New Mexico with his wife Jeanne. He has 5 children.