memory and processing time. The range of optical densities found within this image area ranged from 5 to 400. Since the optical densities extended only from about 200 to 400 for the disc's image, the computational range was truncated by dropping the top 8 bits. Thus, the 8 bits from zero to 255 levels of density are presented in all of the following computer color enhancements.

Figures 8 and 9 are enhancements obtained using only the blue filter scan, that is, there is almost no contribution to this image from green or red wavelengths. A very high contrast color enhancement is shown in Figure 8 using blue picture elements (pixels) on the cathode ray tube monitor to represent film densities associated with the image of the disc and orange and red pixels to represent film densities characteristic of the surrounding sky density. It must be emphasized that there is no particular significance to the colors seen in these computer-enhanced photographs.

Figure 9 shows a black and white enhancement using an undistorted contrast. Much of the top surface detail becomes invisible in both Figures 8 and 9. Presumably this is due to the particular range of wave-lengths that are being reflected or emitted by the disc. Both of these figures show that the sky is relatively homogeneous, the film's crystals (each possessing different sensitivity to light) are approximately random in their spatial distribution, as expected. Also shown is a relatively sharply defined bottom edge of the disc relative to its upper edge. The shadow seen under the disc's lower edge in Figure 6 is barely evident here.

Figure 10 presents an enhancement made using a green filter where purples and blues are assigned to densities which predominate within the image of the disc and yellows are assigned to densities characterizing the background sky. A long vertical scratch exists to the left of the disc's image within this particular emulsion layer. Not only is the sky's density relatively homogeneous in its density but the two regions of greater brightness on the disc become much more apparent. The overall shape of the disc is symmetrical but has more pointed ends. The significance of this is unclear.

A red filter was used to generate the enhancement shown in Figure 11. As was noted in enhancements using a green filter, the dome is missing in this enhancement suggesting that the protruberance on top of the disc is reflecting or emitting wavelengths mainly in the blue-green portion of the spectrum.

Finally, a three-color composite enhancement including blue, green, and red wavelengths was made. Figure 12 presents one such enhancement to illustrate the homogeneity of the sky as well as the emulsion flaw and highlights on the image of the disc. None of the above enhancements show any evidence for a suspension line or thread above the disc.

Site Visit Results

A comprehensive site visit was made by the author on October 7-8, 1983.² Photographs, measurements, and general inspections were made of the entire