Naval Observatory Instruments: 1917

Naval Observatory Instruments: 1917

Time broadcasting instruments at Naval Observatory, 1917. From the Naval Observatory website: "The U.S. Naval Observatory (USNO) provides a wide range of astronomical data and products, and serves as the official source of time for the U.S. Department of Defense and a standard of time for the entire United States." Harris & Ewing, photographer. Vintage photographs provided by LOC. Original Medium: glass negative.