Equipment for Ballistic Geodesy 
by Dr.-Ing. M. Ahrend, Oberkochen 
An increasing number of radar screens, observation telescopes and optical tracking instruments, 
ballistic cameras and photogrammetric cameras are keeping a close watch of our skies. Besides the 
observation techniques based on military security considerations, a large amount of geodetic and 
geophysical research work is going on which was triggered by the potentialities of artificial earth 
satellites. It is applied to the analysis of satellite orbits, to refined methods for determining the 
figure of the earth, and to the determination of points on the surface of the earth ([3], [6], [7], [8]). 
\arious companies, such as Northrop Nortronics, Wild, Instrument Corporation of Florida, 
Askania, Contraves, Perkin-Elmer and Zeiss, have developed specific optical systems for these 
purposes. Designations like Baker-Nunn, Camera, Bowen-Knapp Camera, PC-1000 Camera, CZR 
Camera, BC 4, PTH-60, EOTS Theodolite or Kth 58 E Cinetheodolite identify such instrument 
designs, some of which were developed by scientific institutes ([1], [4], [5]). 
The optical equipment is supplemented by chronometers, synchronizing devices and means of 
transportation to form so-called ballistic stations. A ballistic camera system developed in cooperation 
with German scientists is described in [21- 
The experience gathered from the results of previous measurements indicates that certain modi 
fications of existing instrument systems are desirable. Increasing importance is attached to measures 
aiming at a simplification ol the data reduction procedure. The following paragraphs are intended 
to inform about a few residts of related research work conducted by the development laboratories 
of the Carl Zeiss Works. 
BMK Ballistic Camera 
The BMK/210 mm Ballistic Cameras [2] were first manufactured in 1958 under the scientific 
direction of K. Schwidefsky. Today, they can be fitted with lenses of 300 mm, 460 mm and 600 mm 
focal length (Fig. 1). The basic principle of the azimuthal mounting of the cameras has been pres 
erved. 
Among the different new lens formulae, which are primarily due to W. Roos and R. Winzer, 
special mention should he made of the 460 mm Topar lens which was first manufactured in 1962. 
It is suited for taking high-quality photographs up to a size of 9" X 18". In spite of the long focal 
length, the resolution values for the lens-film combination indicated in Fig. 2 reveal an AWAR of 
over 80 1/mm for the negative area of 7% ,/ X 7*4", which benefits the critical reproduction of star 
images. 
Both theoretically and practically, the mean radial distortion of the lenses manufactured up to 
now remained within 3 microns up to a radial distance of 120 mm (Fig. 3). 
Moreover, the systematic correction of these optical systems has reached such a high level that 
contrary to previous designs, the lenses can now be computed to cover two spectral ranges (the 
so-called A-characteristics, which the mathematicians of Oberkochen applied for the first time to 
the construction of aerial cameras). These types of lenses permit photographs to be taken on both 
panchromatic material and material whose sensitivity peak lies in the near infrared region, without 
the necessity of defocusing the camera. 
The limits imposed on photographic technique widen if the ballistic camera is provided with an 
equatorial mount. The combination of a ballistic camera (in this case, of 460 mm focal length, 
with a negative area of 7*4" X 7*4") with a standard Zeiss 150 mm Coudé Refractor (Fig. 4) offers 
the following possibilities: 
a) Taking of photography as with simple (azimuthal) mounting of ballistic camera, i. e. with 
fixed camera axis during passage of missile across the angular field of the lens; 
BuL 2/1964 
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