| Instrument | : | Level type Wild NA2 with Parallel plate micrometer GPM3 |
| Manufacturer | : | Leica Wild Heerbrugg |
| Country of origin | : | Swiss (both) |
| Manufacturing year | : | 1999 1982 |
This was a superb donation to my collection in 2009. Being a left-over in an inventory, the previous owner had little use for it and decided it would fit better in my collection than on the market. The instrument is of Swiss origin, just as my NK01 and NK10, and signed both 'Leica' on one side and 'Wild NA2' on the other.
The NA2 was originally developed by Wild in 1960 and modernised in 1981. After Wild Heerbrugg merged with the Cambridge Instrument Company plc to form the new Leica Holding B.V. group on April 2nd, 1990,[1] Leica continued the production of the Wild instruments and this is why both company names are shown on the instrument. The NA2 was sold to the Netherlands in January 1999, while the GPM3 parallel plate micrometer on top of it dates from 1982.[2]
With only the Wild N3 being more accurate the NA2/GPM3 combination is a much more sophisticated instrument than the NK10 in my collection. It is equipped with a pendulum type compensator and the parallel plate micrometer allows to make readings down to 0.1 millimetres, while estimating another decimal is possible. The settling accuracy of the compensator is about 0.3" (0.04mm at 25 metres). The original 1960 model allowed to level a 1km double run - using the parallel plate micrometer - with an accuracy of 0.4mm (1σ, 68%), while this modernised version was further improved to 0.3mm (1σ, 68%).
Unlike the NK01 and NK10 this NA2 has no horizontal circle in its base. The 'K' in the type number of the first two indicates whether or not a level has a horizontal circle ('Kreis' in German). Equipped with a horizontal circle this instrument would then have been a NAK2.
For more information, see the Swiss Wild Heerbrugg virtual archives.
[1]: http://www.wild-heerbrugg.com/History.htm
[2]: Many thanks to Jürg Dedual from the Swiss Wild Heerbrugg virtual archives for checking the selling date and manufacturing year for me.