THE BALLISTIC CAMERA SYSTEM
The following discussion has been taken from a previous
paper by D. C. Brown, "Precision Photogrammetry in Missile
Testing".
The ballistic cameras currently employed at the Atlantic
Missile Range, the Wild BC-l's consist essentially of modified
RC-5 aerial cameras mounted on the base of the celebrated Wild
T-4 astronomical theodolite. Three different camera cones are
used: the 115mm Aviogon, the 210mm Aviotar, and the 300mm
Astrotar. The distortion of each lens is calibrated by means of
star recordings to an accuracy of one micron or better. Photo-
graphic recording is done on ultraflat (6 fringe) glass plates
of 6mm thickness.
Experiments have indicated that with suitable shutters,
filters,and photographic emulsions, it is possible to employ
ballistic cameras in daytime operations. At present, however,
ballistic cameras are used almost exclusively at night to record
missile-borne flashing lights. The nighttime operational pro-
cedure at each ballistic camera station is generally as follows.
Precalibration is performed shortly before the missile flashes are
to be recorded. After the precalibration has been completed, the
camera shutter remains closed until shortly before the programme d
missile flashes are expected to appear in the field of view. It
1s then opened and remains opened until the termination of the