the atmospheric transmission of thermal radiation near shot time over the paths from devices to the aircraft. Statistical runs planned for the igamewss using an airbérne light source were dropped, since no spectrometer data were obtained. For SEY: light source failed to operate at zero time; forBRB the light source malfunctioned during an interference test on D—2 night and was evacuated on D—1; fo the light functioned well, and good data were obtained; for Be yaw the aircraft was forced to abort due to engine trouble; and for the Be“ScE3a because of the late hour at which the detonation took place, the transmissometer was saturated by sun~ light. A small number of statistical runs were made on the premise that the atmospheric transmission over the paths of interest might be relatively constant. Reduction of the data accumulated on these runs will be accomplished after return to the laboratory, where the instrument will be calibrated. A preliminary examination of the amplitudes received under no- cloud conditions indicates that atmospheric transmission under these conditions was relatively constant. 2.1.8 Program 9, Technical Photography The objective of Program 9 was to plan, program, and supervise technical and documentation photographic services for all DOD projects participating in the operation. Still photography, in support of projects for illustrating preliminary and final reports, was conducted by TG 7.1, TU-8. A technical motion picture depicting weapon effects tests was assigned to Lookout Mountain Laboratory for location shooting and final production. Technical photography in support of all projects, such as high-speed, timelapse, and function-of-time photography, was conducted under contract with EG&G, Project 9.1 was concerned with the photogrammetric determination of various parameters of nuclear clouds as a function of time and the attempt to establish approximate scaling (yield) relations. It was a continuation of a project first attempted on Operation Castle. Photography commenced at zero time and was continuous for as long as the nuclear cloud retained its visible identity, except for turnaround intervals due to the racetrack pattern flown. At stabilization time, sextant readings to determine approximate height of cloud top and base were made by the photo navigators. Cloud-survey photography was planned for all shots with predicted yields of 30 kt or over. Cursory examination of the film in the field in- dicated that good data should be obtainable on at least six of nine events. Owing to natural. cloud obscuration, negligible results were obtained on one shot and fair results for a limited time on two participations. ~ 37 - f