This Jenoptik Koni 007 automatic level was part of a large donation to my collection together with a 1962 Wild T2 theodolite, a 1969 Wild T2E theodolite, a 1950s Askania Tu400 theodolite, a 1951 Wild N2 level, a 1960s Zeiss Opton Ni 2 level, a 1956 geodetic sextant, and various accessories.

The above mentioned group of instruments once was part of the set of instruments used by the field organisation TGTW of the Survey Department (Meetkundige Dienst, 'MD' in short) of Rijkswaterstaat (part of the Dutch Ministry of Infrastructure and the Environment, responsible for the design, construction, management and maintenance of the main infrastructure facilities in the Netherlands).

The department was closed in the early 2000s and in 2008 the instruments were donated to my collection. The Koni 007 was manufactured by Jenoptik Jena GmbH, a firm that has its roots in Carl Zeiss Jena, and came from the East Germany factory at Jena where it was made somewhere in or before the early 1960s.

Accuracy

The Koni 007 is quite distinctive in shape when compared to other levelling instruments and was known among land surveyors in the Netherlands as the kachelpijp (stovepipe).² Whereas most other levels have a horizontal tubular telescope, a design already used in antique levels, the Koni 007 was built as a periscope. The reason for the shape lies in the compensator, which occupies most of the vertical shaft of the instrument (see figure 11 and figure 12).

The large vertical dimension of the compensator (see figure 11) makes it quite accurate; the sensitivity of it is better than 0.15" or 0.7mm/km. Using this instrument, in combination with INVAR levelling rods, a one kilometre double run could be done with an accuracy of approximately 0.5mm.³

The instrument is equipped with a micrometer (see figure 10), but instead of adjusting a parallel plate it adjusts a pentagon prism in the top of the instrument. The range of the micrometer is only 5 millimetres, for which half a centimetre divided levelling rods were needed.

The telescope has a magnification power of 31.5 times and an objective diameter of 40 millimetres. The image is erect and the cross-hairs are of a wedge type, similar to those in the Wild N3 (see figure 9). The reticle has stadia hairs with a constant of 100.

The instrument came complete with its box, shades and tools (see figure 3). It also contained several brochures dating from 1962, 1966 and 1972. All of them contain a picture of the instrument, the first two of which show it in the green orange-peel finish seen here, while after the first brochure the name changed from Koni 007 to Ni 007, indicating that the instrument has to be from at least before 1966.