record number: | 46 |
instrument type: | sextant – prismatic circle |
manufacturer: | Pistor & Martins Berlin |
serial number: | 302 |
weight: | 1.00 kg |
dimensions (l/w/h): | 21/18/15 cm |
year of manufacture: | 1850 |
instrument set up: | handle, held in hand when measuring |
The prismatic circle, a sextant-like instrument, was made in the 1850s and is one of the oldest instruments in the University of Ljubljana, Faculty of Civil and Geodetic Engineering collection. It measures the angle between the Sun and the horizon, and with additional data from the almanac and a known instant of the Sun's position, the geographical position can be determined. It is held with a wooden handle when taking measurements. The vertical circle has a sexagesimal division engraved on a silvered metal bracket with intervals from 0° to 130° and from 180° to 270°. The reading is done by the two verniers on either side, the unit of the vernier being 20''. The smaller telescope with a Ramsden retractable eyepiece and a 6 mm objective provides a more precise sighting of the target point.
The instrument was completely restored in 2017.
vertical circle | ||
---|---|---|
diameter: | unprotected, 155 mm | |
type of division: | engraved division | |
limb implementation: | silvered metal bracket | |
division: | sexagesimal, 0° to 130° and 180° to 270° | |
unit: | 20' | |
Reading | ||
number of reading points: | 2 | |
reading device: | vernier | |
number of units: | 60 | |
graduation unit: | 20'' | |
Telescope | ||
diameter of objective: | 6 mm | |
type: | Ramsden's retractable eyepiece |