DETERMINATION OF THE DISTORTION AND THE FOCAL LENGTH FOR THE OBJECTIVE-LENS OF THE CAMERA NAFA-3C/25 AND A CAMERA WITH A MOVING FILM,
FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO
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A study of the distortion of camera objectives was made to determine the suitability of photographs taken with the KPP and NAFA-3c25 cameras for precise astrometric work. The stars used in the determination of distortion were at distances of 8-11 degrees from the optical center for the NAFA-3c25 camera and 5-15 degrees from the optical center of the KPP camera. Mean distance between reference stars was 3-5 degrees. Much of the description of the method of analyzing the data presumes that the reader has a knowledge of the Kiselev method described in the above-cited reference. Difficulties are involved in the study because with the NAFA-3c camera it is possible to obtain a photograph with a satellite trail not far from the optical center, but this cannot be done with the KPP camera in the latter case the points to be measured are always at some distance from the optical center or even at the margin of the frame. Coordinates were computed on a Ural-2 computer. Data are given on objective distortion and the dependence of the distortion coefficient on distance of the object from the center of the photograph. Information is also presented on the dependence of the distortion coefficient on azimuth for the two cameras. An important discovery was that the distortion is asymmetrical relative to the optical center. Focal length was determined from a zenith photograph of stars with a good point image star pairs were selected so that the straight line passing through the pair intersected the center of the photograph.
- Unmanned Spacecraft