Rockville, MarylandJune 1963

On the evening of June 27, 1963, a person in Rockville, Maryland reported seeing a bright object in the twilight sky that resembled a half moon in appearance. The object was white in color and about three times as bright as the star Arcturus, one of the brightest stars visible from Earth. Over the course of 30 minutes, the object appeared to shift its position relative to the moon, moving from about 10 degrees to the right of the moon to about 10 degrees to the left. The witness heard no sound and did not observe the object moving across the sky in any obvious way.

The Air Force investigator who reviewed the case noted that the object's lack of apparent motion over such a long period made it unlikely to be an aircraft. The investigator considered whether the object might be a planet. Mars was in approximately the right position in the sky, though Mars typically appears reddish rather than white, while this object was distinctly white. Regulus, another bright star, was about 10 degrees lower on the horizon. The investigator pointed out that stars and planets do not normally change their position relative to the moon by 10 degrees in one hour, which ruled out those explanations. The investigator suggested the sighting could possibly be a balloon, though without wind data from that evening, it was impossible to determine whether a balloon could have remained in the area as observed.

The Air Force's final evaluation of the case was "unknown," meaning the sighting could not be identified as any known object or phenomenon. The full case file is reproduced below as held by the National Archives, spanning 9 pages.