The solar eclipse of June 8, 1937, was the longest in over 1200 years, and this fact was verified by an expedition to Peru headed up by Clyde Fisher of the Hayden Planetarium. The expedition used precise timekeeping instruments from Longines, as pointed out in this ad in Life Magazine, 80 years ago today, May 1, 1944.

According to the ad, Longines chronometers were also used by the planetarium’s expedition to view the April 7,1940 annular eclipse, headed by William H. Barton, Jr.