Accession No
2154
Brief Description
transit theodolite, by Srbastys, Czechoslovakia, c. 1943
Origin
Prague; [Czechoslovakia]
Maker
Srbastys
Class
surveying
Earliest Date
1943
Latest Date
1943
Inscription Date
Material
metal; glass
Dimensions
height 268mm; breadth 225mm; depth 180mm
Special Collection
Provenance
Transferred from Department of Geography, University of Cambridge, Cambridge, England, 05/1969
Inscription
‘Srbastys Praha 922’ (on horizontal circle and on stand)
Description Notes
Metal alloy transit theodlite with khaki finish. Erecting telescope. Squared and milled ring around telescope operates sliding eyepiece focus; secondary eyepiece adjustment. Telescope transits over objective. Bubble mounted outside the vertical circle, viewed by prismatic mirror from eyepiece. Clipping screws. Vertical circle almost completely enclosed. Read to 20” of arc by microscope with a screw to read adjustment and illuminated by small bulb. Clamp and motion screws for vertical circle. Bulb illuminates grid within telescope from below eyepiece. Mounted and A/U frame. Bubble mounted on horizontal circle. Horizontal circle completely enclosed; read by microscope and illuminated by bulb via a reflector on the base of microscope. Clamp and motion screws for vernier plate and horizontal circle. 3 levelling feet on tribrach limbs. Socket for electrical connection on axis end. Trough compass read by microscope. Base for instrument when not in use with spare bulbs. Sighting device which fits onto shoe on telescope.
Condition
References
Events
Description
The Theodolite is a relatively, simple tool used for measuring angles, both horizontal and vertical. They work using the same principles as a protractor, the ‘point A’ is located and the angle noted, and then the telescope is pointed at ‘point B’ and the second angle is taken.
Although primarily used in surveying the theodolite can be applied to both Meteorology and Navigation.
Gemma Frisius proposed the idea behind the theodolite in 1533. At the time new methods of surveying were being used and by combining an Alidade, a magnetic compass and the degree scale on the back of an Astrolabe, the calculations made by modern theodolites could be observed. Unfortunately, this method was not practical due to the combination of instruments. The best of the attempts to simplify the process was the ‘theodolitus’, first described in print by Leonard Digges in 1571.
However, this instrument could only take measurements in the horizontal plane. Despite this it was still thought of as the ‘common’ Theodolite up to the late 18th century.
During the 19th century the Altazimuth Theodolite was considered the most useful theodolite, as it could measure on the horizontal and vertical planes. Three notable types of Altazimuth Theodolite were developed: The Everest Theodolite, the Plain Theodolite and the Transit Theodolite. It is the Transit Theodolite, which is still used today.
FM:43319
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