DKM3

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The DKM3 and its astronomical equivalent DKM3-A are universal instruments (special theodolites) made by the Swiss manufacturer Kern & Co AG .

The abbreviation DKM represents D ouble K rice and M ikrometer - and the "3" for the detail level.

Here is an overview of the different models and their accuracy (360 ° / 400gon):

  • DK1 (direct circle reading 10 '/ 10c; estimate at 1' / 1c) is a small building theodolite
  • DKM1 (10 "/ 10cc; 1" / 5cc) is small triangulation theodolite
  • DK2 (1 '/ 5cc; 6 "/0.5cc) is a universal instrument
  • DKM2 (1 "/ 2cc; 0.2" / 1cc) is a second theodolite
  • DKM2-A (1 "/ 2cc; 0.2" / 1cc) is a second theodolite with an automatic altitude index
  • DKM3 (0.5 "/0.5cc; 0.1" /0.1cc) is a precision universal theodolite for 1st + 2nd order triangulation
  • DKM3-A (0.5 "/0.5cc; 0.1" /0.1cc) is a universal astronomical instrument for astrogeodesy

The whole series was available as DK (without micrometer with direct reading) and as DKM (with micrometer) versions.

It was developed by Heinrich Wild , who left Wild Heerbrugg as co-founder and namesake in 1935 and from then worked as a freelancer mainly for Kern & Co AG . Were presented to the public for the first time in 1938 on the occasion of the International Geometer Congress in Rome.

In 1972 the further development of the DKM2, the DKM2-A and the DKM3-A were introduced.

In addition to the double circle principle, the instruments (DKM3 / DKM3-A) - which, however, have not been built since the merger of Kern with Wild - have further innovations:

The standard is the broken telescope (with which measurements are possible directly in the zenith without deflecting prisms), the lighting and a fine-running recording micrometer for precise determination of the astronomical longitude or sidereal time and for azimuth measurements by means of star passages in the vertical direction of the target. A suitable time system with a pressure chronograph was provided by other providers.

The spectrum of use ranges from triangulations in the network of the first order and astronomical location determinations of high precision to trigonometric height measurements and the most precise control measurements (e.g. of dams). It is also sometimes used in the laboratory and for collimations as a Mire at observatories.

The dimensions of the theodolites are approximately 25 × 22 × 14 cm (H × W × D), the weight 12.2 kg (DKM3-A 14.2 kg), the measurement accuracy about 0.1 ".

With its groundbreaking optical-mechanical innovations, the DKM3-A became the most precise instrument in its class and also fully suitable for high mountains , so that it could be used in numerous state surveys and offices. A few dozen instruments were also exported.

See also

Literature and web links