UFO -- Definition

An object or light seen in the sky, upon the land, or in/under water, whose appearance, trajectory, and general dynamic and luminescent behavior do not suggest a logical, conventional explanation and which is not only mystifying to the original percipients, but remains unidentified after close scrutiny of all available evidence by persons who are technically capable of making a common sense identification, if one is possible. (After J. Allen Hynek.)

Fig. 1.  Image received anonymously in 1994 as color print, without date or photo data.

Fig. 2.  Same image but overlaid with yellow ellipse to locate apparent edge of the disk.