Model : zeiss Th2
Telescope length 155 mm, Height 315 mm
This Zeiss Th 2 one-second optical micrometer theodolite is a highly accurate instrument featuring the unique "ball-and-socket" levelling system. Fields of application include precise angular measurement for traversing, first and second-order triangulations, plumbing, distance measurement with subtense bar and establishing astronomical positions.
Some of the features of the theodolite include:- combined coarse-fine focusing drives, coaxial clamps and fine drives, automatic vertical circle indexing system featuring an X-type pendulum compensator, erect telescope image, convenient carrying handle, optical plummet in alidade and a sighting collimator for rapid and convenient course sighting. The instrument also features a switch which is used for switching between the horizontal (yellow display) and the vertical (white display) micrometer images.
The most important feature of the instrument however, is far-reaching digitisation. Of the 7 figures making up one reading, 6 appear directly in digital form, thus eliminating counting or estimation. The seventh digit is, in addition, presented by a full interval per 1".
The graduation interval for angular measurement is 20' and the micrometer interval is 1". The diameters of the horizontal and vertical circles are 100 mm and 85 mm respectively, and one mirror caters for the illumination of both circles. The sensitivity of the plate level is 20" per 2 mm and the setting accuracy of the compensator is approximately ±0.2". The magnification of the telescope is 30x, the diameter of the objective lens of the telescope is 40 mm, and the shortest pointing distance is approximately 1.6 metres.
The instrument's plastic case is fitted with a number of extra accessories including a plumb bob, a sunshade, an objective tube and a toolkit containing screwdrivers, wrenches and two adjusting pins
The "ball-and-socket" levelling system is also incorporated in the Zeiss Th 4 theodolite (included in collection)
Weight of instrument and container is 5.2 kg and 4.8 kg respectively.
Upright telescope image
School store no: T95
Catalogued in 2000