record number: | 15 |
instrument type: | level with horizontal circle (transit) |
manufacturer: | Neuhöfer & Sohn |
serial number: | 8644 |
weight: | 3.79 kg |
dimensions (l/w/h): | 38/17/22 cm |
year of manufacture: | 1890 |
instrument set up, special features: |
two perpendicular toric levels
levelling toric level by the telescope tilting screw with division, 40 units, on the drum 100 units, turning the screw for one unit means changing the line of sight tilt for approx. 6,6'', the screw division unit represents a length constant of 300 |
The level with horizontal circle (transit) was made around 1890. The levelling is performed by two mutually perpendicular toric levels on the alidade, while a precise levelling toric level attached to the telescope supporting column ensures the levelling of the line of sight. The instrument had an additional positionable levelling level.
A special feature of the instrument is the tilting screw with two divisions – one with 40 units and the other with 100 units. By turning the screw for one unit the tilt of the line-of-sight axis changes for 6.6''. The instrument enables precise optical measurement of distances just like a Reichenbach crosshairs. The constant of the micrometer screw unit is 300.
Branko Korošec describes a similar instrument in his book "Naš prostor in čas v projekciji" (Our Space and Time in Projection) on page 190, where he calls it a "distance meter". This is an unusual name, as the instrument was primarily used as a level, with distance measurement and detailed measurement being of secondary importance.
The instrument was restored, cleaned and lacquered in 2016, and a wooden base was added. The broken pipe of the levelling toric level was replaced and the toric level’s division is not original.
horizontal circle | ||
---|---|---|
diameter: | unprotected, 11 cm | |
type of division: | engraved division | |
limb implementation: | silvered metal bracket | |
division: | sexagesimal/sexadecimal | |
unit: | 20' | |
Reading | ||
number of reading points: | 1 | |
reading device: | vernier | |
number of units: | 20 | |
graduation unit: | 1' | |
Telescope | ||
diameter of objective: | 30 mm | |
magnification: | / | |
type: | Ramsden's retractable eyepiece | |
cross hairs/reticule: | Reichenbach's crosshairs, constant 100 |