for Shots 4 and 5, this barge was 62,200 tcet from the shot barge for each of these shots. For Shot 6, the bolometer was mounted on a power house un Yvonne Istand, 77,522 feet from the shot barge. The modulated bolometer consisted! of two black- Mountain Laboratory, and the terrestrial backup ground photography was made by EG&G in conjunction with Project 13.2. Analysis and reporting of the data were the responsibility of EG&G. One RB-36 and three C-54 aircraft participated in the aerial photography and flew a total of six missions per aircraft. ened platinum wires whose resistance changed with temperature. Usable results were One wire was in cuch ¢f two arms of a obtained from two or more aircraft on all events ex- Wheatstone bridge, which with a mechanically driven cept for Shot 3, where photo results were negative chopper alternately exposed first onc wire and then due to natural cloud cover obscuring ground zero. Preliminary analysis of the Castle cloud data indicated the other wire to the thermal radiation. The application of a de voltage at one end of the bridge resulted exccllent results for the period of H + 10 minutes. Aerial oblique photography supporting Project 3.2, in an ac output at the other end that was ampliticd and recorded on magnetic tape. Crater Survey, was flown by Lookout Mountain Laboratory personnel. This mission consisted of a serics of acrial photographs tracking an LCU during the period of time fathometer readings were being Total tuermal energy was measured by use of Epply thermopiles faced toward the detonation site. The output of tne thermor!ics was recorded on Brown recording potentiometers. These thermopiles were made in the Shot 1 crater. located on Tare, How, and George Islands for Shots flown on Shots 1 and 3 by Strategic Air Command barge near How Island for Shots 4 and 5; for Shot 6, they were located on Fred and Yvonne I{slands. Preshot and postshot crater vertical acrials were reconnaissance personnel. iand 2. Analysis of the crater dimensions was made from this photography by the Army Map Service for Project 3.2. Technical still photography requirements in support of DOD projects were met entirely by Los Alamos Scientific Laboratory photographic personnel. All They were located on Nan Island and on 2 Project 18.3 “High-Resolution Spectroscopy” (W'T-350), Naval Research Laboratory, H Stewart, Project Officer. For Shots 1, 2, 4, and 5, spectrographs of various dispersions and in selected wave-lengih ranges werc located in a concrete bunker at the hase of a 200-fovtower on the gouth end of Nan Island Mbrrors on the project requirements were coordinated and program- med through Program %, including preshot and postshot photography. tower re‘lected light from the detonations «» the viewing slits of the spectrographs. PROGRAM 18: THERMAL RADIATION MEASUREMENTS! For Shot 6, spectro- graph installations were established on Fred and Janet Istands. Project 18.2, Project 18.5 “Thermal Radiation” Project 18.4 “Atmospheric Transmission of Light” Naval Research Laboratory; H. Stewart, Project Officer. Naval Research Laboratory; H. Stewart, Project Officer. Atmospheric trangmissicn was measured over Power-versus-time mcasurements were made by employment of modulated bolometers. These bolom- ed on photo towers on How and Tare Islands for Shots selected paths. To make these measurements, a searchlight of known luminous intensity was mounted 1 and 2. The How tower was 97,975 feet and the Tare tower 77,765 feet from ground zero of these shots. near each zero site for cach selected path and trained on a photocell receiver at the other end of the path. The bolometers were mounted on a barge near How The searchlight beam was modulated by a mechanical chopper (60 cps) and the receiver system was ar- eters were located in 8-by-2-by-8-foot coffins mount- 'Not a formal DOD program. These thermal-radiation projects of DOD interest were sponsored by LASL (see Chapter 8). Publication information for Projects 18.2, 18.5, and 18.4 is as yet uncertain; information on their availability and the availability of the Project 18.3 final (WT) report maybe obtained from LASL. ranged s0 that only light at this modulated frequency was received, thus making the system independent of daylight. The paths for each shot were: Shot 1, from zero site to George, Tare, and Deita Islands (Delta is an artificial island near Able); Shot 2, from zero site to George and Tare Islands; Shots 4 and 5, from zero site to How and Nan Islands; and Shot 6, from zero site to Fred and JanetIslands. 118