Description: The postcards in this gallery are from observatories associated with the Smithsonian. The Smithsonian Astrophysical Observatory established in 1890 in Cambridge, Massachusetts, is one of the Smithsonian’s research centers. Together with the Harvard College Observatory, it forms the Harvard-Smithsonian Center for Astrophysics.The Mt. Wilson Observatory opened in the early
Description: When curators at the Smithsonian National Museum of American History looked at seven radiometers in storage, they learned the instruments had been at the Smithsonian for nearly one hundred fifty years.