Department of the Air Force Committee to Review Project Bluebook, 1966-1967

1000 mun-hours of professional and sub-professional time in the
preparation of graph plots of individual frames of tho film, show
ing apparent and l'e1ative motion of objects and variation in their
1icht intensity. It was tho opinion of tho P.I.L. representatives
that tho objects sighted wero not birds, balloons or aircraft,
were "not renections becau::;o thero was no blinking while passing
through 60° of arc" and were, therefore, "self-luminous". Plots of
motion and variation in light intensity of the objects wore dis
played. While the Panel Members wore impressed by the evident
enthusiasm, industry and extent of effort of the P.I.L. teani, they
could not accept the conclusions reached. Some of the roasons for
this were as follows:
a. A semi-spherical object can readily produce a renection
of.sunlight without "blinking" through 60° of arc travel.
b. Although no da:t.a was available on the "albedo" of birds or
pol?ethylene balloons in bright sunlight, the apparent
motions, sizes and brightnesses of the objects were
considered strongly to suggest birds, particularly after
the Panel viewed a short film showing high reflectivity
of seagulls in bright sunlight.
c. P.I.L. description of the objects sighted as "circular,
bluish-white" in color would be expected in cases of
specular reflections of sunlight from convex surfaces where
the brilliance of the reflection would obscure other portions
of the object.
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