Around 1:35 a.m. on June 21, 1950 three non-commissioned United States Air Force officers watched a disc-shaped UFO as it made repeated passes above Hamilton Field, near San Francisco. Two of the airmen observed from the control tower while another had a separate vantage point. They estimated that the disc-shaped object traveled at a fierce speed, approaching 1,500 miles per hour. At a press conference held the following day the observers revised their story somewhat. They believed the shape of the object had been indistinguishable. This was primarily a result of the intense light pollution surrounding the field. Also, the UFO appeared to be spraying/spewing blue-green or blue light.