| Instrument | : | Total Station type E1 |
| Manufacturer | : | Kern |
| Country of origin | : | Switzerland |
| Manufacturing year | : | 1984 |
I was given this total station in 2009. Based on the manual the instrument was made around 1984. It was made by the Swiss company Kern & Co, founded in 1819 by Jacob Kern in Aarau, a mechanicus making compasses and other drawing instruments. Kern started in a small workshop, then had his first factory built in 1857 at Ziegelrain, which in 1920 moved to Schachen. The construction of railroad tunnels through the Gotthard and Simplon mountains required accurate instruments which Kern - in the meanwhile known as a mathematical instrument maker - was able to deliver.1
The instrument shown here was built more than a century later and was one of the first total stations, an instrument capable of measuring horizontal and vertical angles as well as slope distances and storing these in an electronic memory device (the first total station was the 1968 Reg Elta 14 from Zeiss, but that stored the data on paper tape2). It basically is an electronic theodolite with a detachable distance meter (in this case the DM503). The E1 was introduced in the early 1980s while the attached DM503 distance meter was introduced in June 1983.3
The colour is not coincidentally the same as the Wild Heerbrugg T2 theodolite and TC1 total station. Heinrich Wild designed instruments for Kern & Co after he had severed his connections with his firm Wild Heerbrugg. Later Wild Heerbrugg would acquire a majority interest in Kern and would finally become Leica Holding company on April 2nd, 1990. The plant in Aarau was closed down in 1991.
Being an electronic theodolite the E1 can be used in sexagesimal degrees (360 divisions in a full circle) and gon mode (400 divisions in a full circle) by flipping a switch, while decimal degrees and military units (6400 divisions in a full circle) were available as an option. The instrument has a compensator for the vertical scale and has an angular resolution smaller than 0.3" (arc seconds, 0.0001 gon) and can be read down to 3" (0.001 gon). The instrument's accuracy is 2" (0.0006 gon).
Despite being bulky the distance meter still allows the instrument to transit. A quick field test done when I took most of the pictures - taking 20 distances to a fixed prism at 8.75 meters distance - revealed an accuracy for the distance meter of 0.002m (1σ, 68%). The manufacturer specified the accuracy as "±3mm + 2mm/km".[2] Horizontal and vertical distances are automatically calculated and the latter are corrected for refraction (34ppm) and curvature (68ppm).
The instrument, together with the DM503, weighs a whopping 10 kilograms (15 kilograms with the box). Compared to this my Leica TCRA1101 total station I use for my work is a lightweight at only 6 kilograms (10kg with the box). Not only the weight is considerable, the price was that as well. In 1984 the electronic theodolite with one tripod and one prism would have cost roughly fl.60,000.-, while the distance meter with the Alphacord data collector would have added another fl.20,000.- (in today's money this would have been €57,500.- for the whole set).
For more information, see the Swiss Wild Heerbrugg virtual archives.
[1]: BulletinKern 40 (1988), pp.6-8.
[2]: Deumlich, F., Staiger, R., Instrumentkunde der Vermessungstechnik, (Heidelberg, 2002), p.184.
[3]: The DM503 is advertised on the rear cover of BulletinKern, no. 35 (June 1983), while edition 34 (January 1983) advertised the improved accuracy of the DM502 without mentioning the DM503.