Original photo from project Blue Book taken in 1951
This photo, from the featured document display, is from a report of a UFO sighting in Riverside, California on November 23, 1951. (National Archives, Records of Headquarters U.S. Air Force [Air Staff])
Edit: this was from Project Grudge which was established in 1948 and ended in late 1951 around the time this photo was captured.
Saucers were much more up close and accessible back then.