A view through an aircraft optical gunsight, its reticle marked "100 MILS," photographed at dusk during the Vietnam War. Gunsights of this type were used by pilots of propeller-driven attack aircraft such as the A-1 Skyraider to aim guns, rockets, and bombs against ground targets. The soft blue tones and scattered lights below the horizon evoke the low-light conditions often encountered during close air support and interdiction missions flown near dawn or dusk. Project: 218963