PC-1000

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The PC-1000 is a measuring chamber used by the USA from 1960 as a long-focus satellite camera, which was originally used in the Air Force for military photogrammetry . Some of the approximately 200 copies were tested as astrographs or on satellite stations at the beginning of the space age . The cameras were adapted for this new area of ​​application at the beginning of the 1960s and used for satellite triangulation projects until the 1970s .

Alongside the Russian KFA 1000, the camera is the most tried and tested long-focal length satellite camera and has a focal length between 100 and 102 cm with an aperture ratio of 1: 5 (aperture 20 cm). Special Kodak photo plates in the format 19 cm × 21.5 cm (17 cm × 17 cm of which can be used) were initially used as image carriers , later also in the more common format 18 cm × 18 cm.

The internal orientation of the cameras is extremely stable despite their long construction and the lens distortion is only about 5 µm. This means that measuring accuracies of around 1 "can be achieved on individual plates, which is twice as high as the more compact cameras developed later. The first major application was the stellar triangulation with the ANNA 1B flashlight satellite for mutual measurement of ground stations. At a distance of 500 to 1500 km, only a few simultaneous recordings with accuracies of ± 0.5 "achievable. Later the cameras u. a. used for the world network of satellite geodesy completed in 1974 .

Around 1965, a groundbreaking method was successfully tested: photographing a satellite illuminated by a laser station in front of the star background in order to get the exact direction at the same time as the distance measurement .

literature

  • Myron W. Lawrence: Calibration of PC-1000 Cameras by means of Star Photography (= Ballistic Research Laboratories. Memorandum Report. No. 1468, ZDB -ID 1012804-9 ). Ballistic Research Laboratories, Aberdeen MD 1963, online .
  • Armando Mancini: Space orientation and geodetic azimuths of long lines from observations of the ANNA Satellite. In: Bulletin Géodésique. Volume 76, No. 1, 1965, pp. 97-113, doi : 10.1007 / BF02526832 .
  • И. С. Шкловский, П. В. Щеглов: Оптические наблюдения искусственных спутников Земли. In: Успехи физических наук. Vol. 64, 1958, pp. 417–424, doi : 10.3367 / UFNr.0064.195803a.0417 , (In German: IS Šklovskij, PV Ščeglov: Optical observation of artificial earth satellites. In: Artificial earth satellites (= progress in physics. Sonderbd . 2). Akademie-Verlag, Berlin 1959, pp. 349-357, doi : 10.1002 / prop . 19590071423 ).
  • Owen W. Williams, Robert L. Iliff, Michael S. Tavenner: Lasers and satellites: A geodetic application. In: Bulletin Géodésique. Volume 80, No. 1, 1966, pp. 151-156, doi : 10.1007 / BF02527045 .