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Three topics are briefly reviewed here :
The author consulted with a person [I wish to thank Mr. Gordon Holt for his professional assistance in this phase of the analysis]who had previously worked for a well-known manufacturer of Frisbees. He explained the necessity of having a smoothly curved leading edge at the circumference of the disc and tiny microgrooves in the top surface in order to create a lifting force during its spinning flight. He suggested that the addition of a dome-like structure to the top would probably reduce or destroy this aerodynamic lift. The author (later) proved that this was indeed true. The author also contacted various toy stores to inspect various Frisbee models. A total of seven different models were inspected. All possessed a glossy (specular) outer surface. Most had reflectances of about 80% or less. Of the six models produced before 1981, only two had paper labels, the other four 6 had colorful embossed drawings centered across the top surface.
Men's and women's world records for throwing Frisbees were obtained from the International Frisbee disc Association (IFA). This organization has hosted tournaments which have become qualifying events for the World Frisbee Championship. It was discovered that the men's outdoor distance record is 166 m (540 feet) and the women's record is 122 m (397 feet). These records were set in 1983 and 1980, respectively and are meant only to indicate the general range of human capability for this skilled activity. The men's world record for maximum time aloft is 15.5 seconds (1981); the women's record is 11.4 seconds (1980).
The linear width of the disc's image on the negative was 0.98 mm. The width of the 36 mm frame was equivalent to a horizontal angle of 48°. The useful ratio can be formed:
where: X = the angle subtended by the disc. This angle is 1.307°. Therefore, Tan 1.307/2 = 0.0 114 = (W/D)2 where: W = the assumed object width and D = the separation distance between the camera and object. Letting W = 9 inches, D = 32.88 feet which exceeds the hyperfocal distance. If the disc object was 10 or 50 feet in width it would have been 438 feet or 2,192 feet from the camera, respectively. And if the disc had been hovering directly over the mountain (i.e., 7,580 feet away) it would have been 173 feet in width.
Assuming that the camera shutter speed was 1/125th second and the disc image was produced by a typical Frisbee travelling at 10 feet per second, a 9 inch diameter disc moving normal to the line of sight would move 0.96 inches in his duration. Approximately 9.3% of the Frisbee's diameter would show up as a blur on the leading and trailing edge of the Frisbee's photographic image. There is virtually no blur visible on the photograph in question which strongly argues that the disc was not travelling normal to the line of sight. If it was motionless it would be far more difficult to perceive, particularly if the photographer was (a) looking through a camera's optics and (b) was not expecting to see anything hanging motionless in the air.
It is highly unlikely that the object photographed was a commercially available Frisbee. There are significant top surface contour differences between a Frisbee and the photographed disc. This was shown by a careful comparison of photographs of a Frisbee model with scale dome oriented the same as the photographed disc and illuminated by sunlight under the same angular conditions. The surface reflections were markedly different in each case. In addition, the presence of the tiny, concentric micro-grooves on all Frisbees would not be expected to yield a sharp contrast gradient as is seen in Figures 7(b), 8, and 9. When the author attached a light-weight dome to a Frisbee it would not fly very far nor very high. It is problematical whether another person could have achieved such a feat. The author inspected the frame immediately following the frame in question and found that it had been taken in Campbell River following the trip north. The immediately preceeding frame was also located. It showed Mr. D.M. and their daughter standing in front of a small pond at the Provincial park on the day the photograph had been taken, exactly as stated by the photographer. If someone had tossed a model up into the air in order to photograph it, only one photo was taken. It is fortuitous that such a clearly focused image was obtained on the first try, if this is what happened. Furthermore, this explanation does not stand up under scrutiny of the author's in-depth interviews and site visit. The fact that the photographer stated that she was taking a photograph of the mountain (and not of a UFO disc or model) is further supported by the fact that the top of the mountain was well centered in the photograph. The object was not centered. The lack of any image blur suggests that the disc was nearly motionless which would make it more difficult to see, other factors equal.
In summary, this investigation has shown that a mature adult with high credibility and little or no interest in UFO phenomena obtained a single, colored, sharp imaged photograph of an unidentified aerial disc-like object. Her subsequent reactions to seeing the disc's image on her photograph produced surprise and dismay as well as the normal array of "answer-seeking" behavior. She has not capitalized on having such a photo [See footnote 5] and still acts somewhat embarrassed at having taken it without seeing the disc. The disc's identity has not been identified to date.
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