TODIS base range finder

 © Technisches Museum Wien, Photo: Peter Sedlaczek
Collection Area
Technical and Scientific Principles
1970 - 1979
At the moment this object is not published in the museum.

The distance of inaccessible points in open territory cannot be ascertained using tape measures. Optical range finders are used instead.

Optical measurement of distances is based on the principle of binocular stereoscopic vision. If a person looks at a distant object, then slightly different images are received in each eye due to the distance between the eyes. In order for the images to converge, the eyes must turn slightly towards each other. This becomes particularly apparent in the case of very nearby objects.

The base range finder from the collection of the Technisches Museum Wien (Vienna Technical Museum) works in exactly the same way. Two telescopes are mounted on a rail at a distance of around one metre (the "base"), and are sighted on a remote point. The two images are converged using a microscope. The distance is calculated from the angle taken by the optical axes. At 40 m distance, the accuracy is at least ± 1.5 cm. This method is generally used in surveying technology and is called triangulation. Using significantly larger base lines, such as the diameter of the earth or even the diameter of the earth's orbit, even the distance of the moon, the sun or other celestial bodies can be determined.

Manufacturer: F. W. Breithaupt & Sohn GmbH & Co. KG, Kassel
Date of construction: approx. 1970

Inv.Nr. 68413/1

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