FIGURE 1
The image on the left is from 61H3, and the one on the right is from 62H3.
Both were scanned at the same resolution 2700DPI from the 8X10 inch negatives,
with one pixel equal to about 1/4 the quoted resolution for the Lunar Orbiter
camera at a 3:1 contrast ratio.
In Frame 61H3, part of the object is missing where it has been cut off at a framelet boundary (misalignment of framelets was a problem with many of the Lunar Orbiter images).
In Frame 62H3, it can be seen that there is a rounded lobe on the right side of the object that matches the one on left, suggesting that the object has a mirror-image symmetry. In 62H3's complete image of the object, the boundary between its base and the lunar surface appears to be unusually linear. This apparent base line is between the two white arrows pointing toward each other in Figure 1. The apparent regularity of the objects' base and mirror-image symmetry of its top would seem to be very surprising features in a common lunar boulder.
The substantially greater width of the shadow near the Cuspid in 62H3 has little effect on the shape of the profile of the object previously derived from compressing the shadow's image from Frame 61H3 because the profile's width is influenced more by the width of the shadow farther from the object, which is the full width of the object in the first photograph and is not cut off by the framelet boundary. FIgure 2 shows the profile resulting compression of the Cuspid 5 shadow in Frame 61H3 after first moving the two adjacent framelts apart by the amount indicated to be missing in 62H3. The slope illumination angle of 6.9 degrees used to produce this profile is in the center of the range of angles previously estimated from the apparent penumbra. As will be shown on the next page, that angle is probably the best estimate of the illumination angle because it is supported by photometric analysis.
FIGURE
2 Profile of Cuspid 5 created from the shadow of the object from
LO2-61H3 taking into account the area missing due to framelet overlap for
a 6.9 degree sun elevation above the slope on which the shadow is cast.
The image on the right is the same as the one on the left, with the additions
of outlining to indicate the apparent edges of the object.
Due to some unavoidable blurring caused by the resizing algorithm used to compress the shadow in Figure 2, it is difficult to see exactly where the shadow boundary is. That might lead you to wonder whether I've been a little too imaginative in how I drew the outline of the Cuspid on the version to the right in Figure 2. However, you should be able to satisfy yourself that the above profiles are reasonable given the sun angle of 6.9 degrees by doing the fallowing:
FIGURE 3
A one-Kilometer wide crater to the north of the Cuspids from LO2-62H3.
This image was scanned at 337 DPI from the negative. The main group of
Cuspids are a few hundred meters to the right of the position of this image.
FIGURE 4 "Cuspid 6," the Crater Cuspid. Object and shadow on the eastern rim of the crater of Figure 3.The image was scanned from LO2-62H3 at 2700 DPI. This shadow and the part of the crater it is near were not visible in LO2-61H3 because they were off the edge of the photograph. The image has been rotated 90 degrees counter clockwise here from its orientation in Figure 3 so that the entire shadow fits on the monitor. Note the bright object at far left of the image, which is casting the shadow.
The shadow is obviously being cast downslope into the crater, which might lead the astute observer to suspect that the shadow's length has been greatly exaggerated by the slope in the way previously explained. However, the slope is much less along the crater rim in the direction the shadow points than it would be if the shadow were pointing toward the crater's center, where it is deepest. This couuld mean that the object casting the shadow might still have a significant height.
But this "maybe" and "might be" sort of argument will never lead to a reasonable estimate of what the shape of the object actually is. The shadow is too small to detect any indication of a penumbra, which was previously used for a rough estimate for the height of Cuspid 5. We have learned, however, that the Lunar Orbiter negatives do contain sufficient photometric information for estimates of the terrain slopes. A preliminary analysis not only suggests that "Cuspid 6" does have an anomalous morphology, but the same technique supports the estimate previously made for the shape of Cuspid 5. An image displaying the probable profile of this new object will be shown on the next page, but first you'll have to wade through some discussion of basic photometric principles before you get to it.
