| record number: | 56; 57 |
| instrument type: | self reducing tacheometer with map-drawing board Karti |
| manufacturer: | Carl Zeiss Jena |
| serial number: | 241247; 180741 |
| model: | Dahlta 010; Karti |
| weight: | 3.81+0.65; 4.38 kg |
| dimensions (l/w/h): | 22/16/27 cm |
| year of manufacture: | 1968; 1965 |
| centering and leveling the instrument: |
optical plummet
circular level toric level on the alidade compensator |
The Carl Zeiss Dahlta 010 self-reducing tacheometer was made in 1968 and the Carl Zeiss Karti map-drawing board in 1965. The map-drawing board is mounted on a tribrach, and the tacheometer is mounted on the map-drawing board. The drawing part of the board rotates around its centre at the same time as the instrument rotates around the Z-axis.
The tacheometer, with its special crosshairs shape, allows direct measurement of horizontal length and height difference. The board allows automatic transfer of the measured direction of the instrument to the mapping guide, on which the length application division is located. Several scales can be used to apply lengths: 1:1000, 1:2500 and 1:5000. The maximum resolution of such mapping is 0.1 mm. The possibility of direct mapping in the field offered by this technological solution has not been taken up in the development of measurement technology.
The instrument is in the state it was in when it was originally taken out of service. The map-drawing board has hardly been used and is like new.
| horizontal circle | vertical circle | |
|---|---|---|
| diameter: | protected, 96 mm | unprotected, 74 mm |
| type of division: | engraved division | engraved division |
| limb implementation: | glass bracket | glass bracket |
| division: | sexagesimal/sexadecimal | sexagesimal/sexadecimal |
| unit: | 1° | 1° |
| Reading | ||
| number of reading points: | 1 | 1 |
| reading device: | scale microscope | scale microscope |
| number of units: | 60 | 60 |
| graduation unit: | 1', estimation 6'' | 1', estimation 6'' |
| repetition: | Mahler membrane | / |
| Distance measurement | ||
| principle: | optical, parallactic triangle with a variable angle and a base on a vertical staff | |
| precision: | 10 – 20 cm per 100 m for distances, 5 to 10 cm per 100 m for height differences | |
| range: | up to 300 m, depending on the tacheometric staff length | |
| Telescope | ||
| diameter of objective: | 40 mm | |
| magnification: | 25 x | |
| type: | telescope with internal focusing | |
| cross hairs/reticule: | horizontal hair, two distance hairs, constants 100, 200, four elevation hairs, constants 10, 20, 50, 100 | |
| Map-drawing board Karti | ||
| disc / drawing board diameter: | 280 mm / 250 mm | |
| interchangeable scales: | 1:1000, 1:2500, 1:5000 | |
| magnifying glass: | 3 x | |
| maximum mapping accuracy: | 0,1 mm | |