| record number: | 13 |
| instrument type: | theodolite |
| manufacturer: | R & A Rost Wien |
| serial number: | 3631 |
| weight: | 5.51 kg |
| dimensions (l/w/h): | 25/22/30 cm |
| year of manufacture: | 1890 |
| centering and leveling the instrument: |
plumb bob
two perpendicular toric levels on the alidade vertical circle: vertical circle level, tilting screw precise reversible levelling toric level |
The theodolite was made around 1890. The instrument is levelled by two mutually perpendicular alidade toric levels. A robust instrument, typical in functionality and precision of the most numerous theodolites of the time, it has all the classic accessories for setting up and determining measurement values. The two circles are open and the division on the two verniers, placed diametrically, is read with the help of microscopes; the resolution is 20''. The Reichenbach shape of the crosshairs complement the instrument and turns it into an optical tacheometer.
The instrument was completely restored in 2016 and the two diaphragms next to the reading lens of the vertical circle division are new.
Characteristics
| horizontal circle | vertical circle | |
|---|---|---|
| diameter: | unprotected, open, 15 cm | unprotected, open, 12 cm |
| type of division: | engraved division | engraved division |
| limb implementation: | silvered metal bracket | silvered metal bracket |
| division: | sexagesimal/sexadecimal | sexagesimal/sexadecimal |
| unit: | 10' | 10' |
| Reading | ||
| number of reading points: | 2 | 2 |
| reading device: | vernier | vernier |
| number of units: | 30 | 30 |
| graduation unit: | 20'' | 20'' |
| repetition: | clamping and micrometer screw | / |
| Telescope | ||
| diameter of objective: | 30 mm | |
| magnification: | 17 x | |
| type: | Ramsden's retractable eyepiece | |
| cross hairs/reticule: | Reichenbach's crosshairs, constant 100 | |