The Kern DKM2-A has steel construction for maximum stability and precision. Maintenance-free compensator for vertical indexing. Coarse and fine orientation-drive to accurately set horizontal circle. Optical plummet in alidade. This instrument is equipped with a detachable tribrach in lieu of the Kern base with a bayonet-lock attachment and forced-centering to tripod or trivet. This model is therefore interchangeable with other tribrach theodolites with 5/8 x 11 inch threads.The successive terrestrial version was named the DKM2-AE, with the added E standing for erect or upright telescope image.High measuring accuracy, simple operation and maximum stability under any environmental conditions, these are the design parameters on which the construction of the DKM2-A is based. The high resolution telescope produces a sharp image with maximum contrast. The digital readout virtually eliminates reading errors. Use of tempered steel for both vertical and horizontal axis as well as for all components influencing measurements, guarantees highest stability and imparts confidence when instrument is used under most adverse conditions.At a high intrinsic accuracy, the DKM2-A is simple to operate: its digital readout is explicit. The operating knobs are in logical sequence and thus assure operating convenience. Both tangent screws are equipped with coarse and fine drive, providing precise pointing.Two-speed vertical and horizontal slow motion screws. A mechanical speed reduction is built into both tangent mechanisms. When pointing with the coarse drive, the telescope reticule intersect is moved slightly past the target. When retracting, the speed-reduction gear is automatically engaged, thus at the same rate of knob rotation, the rate of reticule movement is reduced to half speed. As a result, more precise pointing is achieved.The digital circle readout for both horizontal and vertical circles appears simultaneously in the circle reading eyepiece. A glare-free readout is assured by a yellow-green filter, hence no tiring of the eye.Essential for a one-second theodolite, the DKM2-A has the reliable Kern double-circle reading principle. The human eye is most sensitive for estimation of equal distances between two narrow vertical lines; thus the “symmetry-setting” system which has proven itself, is retained. The respective circle readout, designated with “V” and “H”, is accomplished with optimum accuracy, setting the single vertical line evenly between the double-lines. All parts influencing the measuring accuracy are mounted on a steel plate in the immediate vicinity of the circle. The resulting answer, projected to the reading eyepiece by viewing optics is therefore undistorted. Up to and including the 10 second graduation, all values are read and directly in digits. The tiring and error-producing reading of divisions or estimating of intervals, is eliminated. Only the single second must be read on the scale graduations.Coarse and fine drive for circle orientation. The horizontal circle is quickly rotated through 360 degrees with the coarse drive and set easily and precisely to any desired value with the fine drive. Both drives are protected by a hinged cover against accidental operation.
