The Baker-Nunn Camera, designed by James Baker and Joseph Nunn, was created to observe both natural and man-made satellites orbiting at a great altitude. This high-precision telescopic tracking camera was used by the Smithsonian Astrophysical Observatory (SAO) to track artificial satellites from the 1950s to mid-1970s. The SAO set up a highly successful optical tracking system using a network of Baker-Nunn cameras at twelve tracking stations located in Argentina, Australia, Curacao, India, Iran, Japan, Peru, South Africa, Spain, and at three sites in the United States.