| record number: | 32 |
| instrument type: | theodolite |
| manufacturer: | Carl Zeiss Jena |
| serial number: | 46486 |
| model: | Th IV |
| weight: | 5.81 kg |
| dimensions (l/w/h): | 19/14/26 cm |
| year of manufacture: | 1939 |
| centering and leveling the instrument: |
plumb bob
circular level toric level on the alidade, centrally set vertical circle level levelling toric level |
The theodolite was made in 1939. It follows the Zeiss technology of the time in terms of design and method of operation. The typical modern design of the time, similar to the Th III model, facilitates the measuring process. The cylindrical axis clamped to the detachable base, the ball bearings, the glass circles, the reading by means of a single microscope and the centric alidade toric level are some of the important technological improvements. It differs from its more precise sibling in the way it determines the readings on the circles. The scale microscope has a graduation unit of 1'.
The instrument is best suited for polar detail measurements. In 2016, it was restored and newly lacquered and the screws were cleaned. The color of the instrument is perceptibly different from the original color.
| horizontal circle | vertical circle | |
|---|---|---|
| diameter: | protected, 90 mm | protected, 70 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' | 1' |
| repetition: | Mahler membrane | / |
| Telescope | ||
| diameter of objective: | 35 mm | |
| magnification: | 28 x | |
| type: | telescope with internal focusing | |
| cross hairs/reticule: | Reichenbach's crosshairs, constant 100 | |