and documented by means of printed forms and check lists. Typical forms worked up for the Pinon shot, are given in Figures 10 and 11. The Photo Plan sheet is used to outline the photographic effort contemplated for a given shot; as details become available these are added to turn the sheet into a detailed instruction sheet from which the entire station may be es- tablished. A separate sheet is prepared for each station to be used; for Pinon there is only one such station. The Photo Loading Chart (Figure 11) gives instructions as to the type of film and identifying number, which is perforated through the film base, and also information as to exposures and settings. In addition, the Loading Chart provides a running record as to the status of the film-load, indicating how long it has been in the camera, and when it needs to be replaced. The station is set up according to these charts, and is tested in several simulated dry runs. The dry-run films are processed and are exam- ined to be sure that exposures are correct, that speed-marks have been placed on the film at proper density, and that the cameras operate at the specified speed for the prescribed time interval. A day or two before the shot, the final film is loaded into the cameras, and the station is carefully checked out by two operators who use a master check list. Sample check lists are presented in Appendix I and II at the end of this chapter to show the sort of information that is checked, double- checked, and certified by signature of the operating crews. Of course it is necessary to check the check lists during dry runs, to assure their complete adequacy. In the event of postponements for a day or two it is customary to turn the cameras over by hand, to advance a few feet of film through the camera gate. This eliminates the effects of sharp bends and loops, which might take a permanent set and which might break during the sudden acceleration of the camera. In case the postponements are repeated for five days or longer it is customary to replace the entire station film-load. 22. Analysis Equipment The analysis program embraces the reading of calibration films and the determination of focal lengths, the reduction of survey data and the calculation of magnification factors, the reading of fireball images and the £ calibration of the optical systems employed, the determination of the tim OG. i Cd | -29 -