Maker

Carl Zeiss, Jena (Germany)

Model

Th 1

Serial Number

16429

Dimensions

Telescope Length 135mm, Height 215mm

Image

Description

This pioneering theodolite was designed by the Swiss instrument maker Heinrich Wild (1877-1951) and produced by Carl Zeiss, Jena and is recognised as the first optical theodolite. It is the first optical theodolite with graduated 'glass' circles and the first to incorporate the optical coincidence micrometer with parallel plates which was invented by Wild in 1918. The instrument was typically used for triangulation networks and traversing. It is considered as an important historical instrument which earned great merit in modernising surveying instruments. 

The horizontal and vertical circles are divided into 400 grads. 

History & comments

The Th1 optical theodolite was first produced in 1922 by Carl Zeiss, Jena, featuring all of Heinrich Wild's modernising designs. These designs included interior focussing, cylindrical axes, split level bubbles and plane parallel micrometers.

Conservation

In a box

Condition

Good condition, well maintained

Remarks

• Production commenced in 1922
• Instrument previously owned by the S. G. O. (Surveyor General's Office)
• Inscription: 'S. G. O. No. 1001'
• Catalogued by T. Ko
• Updated by F. Pall

Dates

Manufactured in 1922 (approx). Catalogued in 1997