0224
   OPTICAL MICROMETER THEODOLITE  
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  Surveying Instrument Collection 

Maker

Wild, Heerbrugg (Switzerland)

Model

T2 (E)

Serial Number

26302

Dimensions

Telescope length 150mm, Height 270mm

Image

Wild T2 (E) Optical Micrometer Theodolite

Description

This is the famous Wild T2 Micrometer Theodolite and due to its compact and sturdy construction it has been used by surveyors all over the world ever since Heinrich Wild created the first model T2 back in the 1920's. The instrument shown above is the Wild T2 (E) which was a follow-on of the original instrument and was manufactured in the 1950's. It is commonly referred to as a "universal" theodolite, since it is capable of coping with virtually any problem in surveying, engineering and industry. Some of the typical surveying applications include triangulation, precise traversing, astronomy, tacheometry, engineering, cadastral, mining, setting out and optical tooling. 

The theodolite is supplied with a detachable tribrach (GDF-6) to which it is securely fastened by a special clamping device in such manner that the instrument cannot possibly fall down. The tribrach is also fitted with a built-in optical plumb, which makes centring of the instrument over terrain point possible.

Instead of incorporating only one illuminating mirror for reading both the horizontal and vertical circles, there are two illuminating mirrors, one for the horizontal circle and one for the vertical circle. This is actually a slight disadvantage since the mirrors are located at different sides on the instrument and so reading the circles may not be as efficient. 

The theodolite features a coincidence micrometer circle reading system. The graduation interval of the horizontal and vertical circles is 20' and the micrometer interval is 1". The readings are made in the T2 with the circle reading microscope mounted adjacent to the telescope eyepiece. The magnification of the telescope is 28x, the diameter of the objective lens of the telescope is 40 mm, and the shortest pointing distance is approximately 1.4 m. The graduated circle diameter of the horizontal circle is 90 mm and the vertical circle diameter is 70 mm. The bubble sensitivity of the plate level is 20" per 2 mm run, and the setting accuracy of the 'split image' vertical circle level (altitude bubble) is 1".

Also included in the collection are four T2 attachments:- 

(1) A striding level [0229]

(2) Rotatable objective penta-prism with counter-weight [0230]

(3) Two diagonal eyepieces [0231]

(4) 30 Astrolabe Attachment [0245]

 

History & comments

The original Wild T2 was one of the first theodolites to feature glass circles and an optical reading system, after Wild's Zeiss Th1 (see 0203).

Conservation

Metal container

Condition

Slight visible signs of paint peeling on both the instrument and the container.

Remarks

 

  • Weight of instrument and container is 5.6 kg and 2.1 kg respectively.
  • Inverted telescope image
  • School store no: T34
  • Catalogued by F. Pall

Dates

Purchased by UNSW on 30 April 1951. Catalogued in 2000 and 2010.

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