Michael Collins’s personally-owned and -used ‘Log Log Duplex Decitrig’ slide rule manufactured by Keuffel and Esser, model N4081-3, measuring 12.5″ long and 1.5″ wide, engraved on the side with a copyright date of 1947 and serial number of 500116. Includes the original brown leather case and instruction manual. The slide rule shows extensive use, with cracked plastic to the slide mechanism, soiling, and toning. Keuffel and Esser was a premiere maker of drafting supplies, slide rules, and similar instruments, and this model of slide rule was one of its most popular products and a mainstay of students and engineers from the 1930s through the 1960s. This instrument was clearly well-used by Collins throughout his long career that brought him to the moon. Pilots were trained to use slide rules in flight school, and astronauts carried them during spaceflight for making routine calculations or in case of emergency. A desirable personal item from the Apollo 11 astronaut.
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