23857122-0457-180273-0391

Ltr, ERH, to CG, AMC, Subj; Analysis of Proj. "Grudge" Reported Incidents "one flying saucer; two flying saucers, three flying saucers" ---etc, At a normal speaking speed. On the other hand it is not easy to count , seconds and at the same time make all the other desirable observations. It must be remembored that when a person is excited his estimates of time are apt to be rather inaccurate. d. Bstimation of the elevation angle of the object. Almost all persons will overestimate elevation angles. This tendency can be reduced by the observer extending one arm vertioally and the other horizontally to observe a 90° angle. The vertical arm can then be lowered to point to the observed object. In this way the observed angle can be compared with a 90° angle and a more accurate estimate obtained. 6. It is realized that it might not be possible for an observer to perform the opeations suggested in the preceding paragraph, during the period the object is sighted. If he would immediately reoonsider what he saw and then estimate such measurements, he should be able to give quantitative answers accurate to at least 25%. In interrogating observers, they should also be asked to reconstruct their observations and then estimate these same factors. It is suggested that instructions for making. such quick and estimated observations be given to weather observers, control tower operators, civil police, forest and fire rangers, and other such people who might have good chance of seeing unidentified flying objects. If any information concerning unidentified flying objects is given to the public, instructions for reliable observa- tion should be included. 7. This organizat:on will be pleased to be oi any further assistance required in connection with this matter. 8 FOR THE COMMANDING OFFICER: 3 Incls /s/ &,. C. Trakowski, Jr. 1. List of balloons A. C. TRAKOWSKI, JR. launched (in trip) Captain, USAF 2. &* X 10" photo print Director, Base Directorate of plastic balloon for Geophysical Researoh 3. i" x 5" photo print of plastic balloon h $-31,560 Declassification Authority: NND 57565