Project Blue Book File on Tremonton Film, Utah, 1952

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white; no strong colors are noted. As to similar motion, a definite grouping of objects is noticeable. The first two sequences, taken with the sky as a light blue, show what probably are two groups of three objects each, and two groups of two each. The final sequence, against the dark blue sky, shows four pairs of objects, with the fifth pair having drifted upwards, out of the camera's field of view.

6. If the objects are reflecting, the "fade-in" and "fade-out" are caused by changes in attitude of decidedly non-spherical objects, as in Answer 1 above. On the other hand, if they are light sources, the variation could be associated with their maneuvering activity.

7. and 8. As explained in the opening paragraph, the objects are only small bright spots on the film. When they dim sufficiently, they become invisible; no dark spots can be identified with these objects. The only visible motion in any single frame is with respect to the camera's field of view. Slow motion examination of successive frames suggests a general flight pattern of sweeping skew curves in space. This concept of object motions produces no sharp breaks in their apparent flight paths, and also makes it practically impossible to detect rapid accelerations or decelerations along these paths.

9. In the sequences during which the camera was held motionless, to record the angular velocity of a single object, it is possible to measure this velocity. Three such passes can be seen. The first was incomplete, picking up the object near the center of the frame. The second and third passes were complete, from one edge of the field of view to the other.

Figure I shows the actual tracings of the object from frame to frame for both Passes No. 2 and No. 3. The distance from lens to screen was 100 inches. The focal length of the projection lens was 2 inches. The enlargement of Figure I over the actual negative size is therefore 50 times. Camera and projector errors, plus small hand-held camera motions, probably account for the deviations from a straight line path. The average calculated angular velocity for both paths is about 2.1 degrees per second. Detailed computations are given in Appendix I.

10a. A slow motion viewing, plus single frame position plots, suggest that the objects are maneuvering in definite formations. However, successive identical positions are not indicated when position plots from any two frames in a sequence are superimposed. For instance, the first sequence of movement lasts 160 frames or 10 seconds. During the first seven seconds, clear plots for all 10 objects can be made. These plots were made at half second intervals or 8 frames apart.

10b. Figure II represents a possible set of flight paths for this interval, derived as explained in Appendix II. It should be remembered that Figure II very likely contains some indeterminate and non-constant camera motion, both horizontal and vertical, caused by tracking the formations. This means that the directions and curvatures as shown may be appreciably different from what a stationary camera would have recorded. However, Figure II does help visualize

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