almost transits the light of the background in a transparent manner. It is of interest to note that the general orientation of this left-hand boundary of the image runs North and South rather than being parallel with the visible longitudinal axis of the disc. This irregular edge is shown more clearly in following computer enhancement photographs.

The top (North facing) edge of the disc is in extremely sharp focus with not even the grain structure of the film being apparent, whereas the entire top "surface" of the disc shows a mottled graininess which could be representative of a diffusely reflecting surface.

If the disc image was of a real object travelling at a high rate of speed relative to the film plane, then one would expect a blurred image on both the leading and the trailing edge. This did not occur here.

Fifth, the entire image is in sharp focus suggesting that (a) the shutter speed was fast, (b) the disc was not moving relative to the earth background, or both. It is known that the exposure lasted 1/500 second which would "stop" a slowly moving object but not necessarily a fast-moving one.

Of equal interest is the calculated maximum dimension of the disc if it was located at the earth's surface, 10,000 feet away from the camera. The 4.2 mm length of the image is equivalent to an object 210 m in length or 683 feet. The object cannot be farther away than this.

The apparent shadow structure on the disc deserves further comment. Using the location on the ground where defined clouds produce shadows, straight (sun) lines were drawn, all of which should point back toward the sun. Interestingly, these lines are not parallel but converge to a common point near the bottom left corner of the photograph. This suggests that the camera's optical axis was not pointed gravitationally down to the earth but at an oblique angle.

Figure 6 is a photographic enlargement of the negative contrast in which the film's grain structure is apparent. In this regard, there is no distortion of the grain anywhere around the disc's image which suggests that it was not the result of a double exposure. Nor is there any obvious indication of heat-produced atmospheric distortion around the object. There are no visible lines to or from the disc. The magnification is identical to that of Figure 4. It is noted that the finite thickness of the disc is apparent, as is the edge sharpness on its right and diffuseness on the left.

All available photographic evidence was studied for the existence of a shadow of the disc. Since the lighting geometry is known, the existence of a shadow would make it possible to calculate the linear size of the disc. The sun-line extending from the disc's location was traced on the negative, positive prints, and digital enhancements and any evidence for an approximately symmetrical shadow was sought. None was found. In this regard it