Maker

Wild, Heerbrugg, Switzerland

Model

Stereo Micrometer

Serial Number

271

Dimensions

320 x 50 x 20 mm

Image

Description

This stereomicrometer by Wild Heerbrugg was usually supplied with the WILD ST4 Mirror Stereoscope. The measuring range of the device is 200 to 270 mm. The device includes movable glass plates (25 x 80 mm) with three different measuring marks (circle, dot, cross). One of the two carriers for the glass plates can be shifted on its own by 55 mm. The two marks can be moved 175 - 270 mm to suit the stereo images and stereoscopes at hand.

The micrometer range is 40 mm. The WILD ST4 is designed for stereoscopic viewing of two 23 x 23 cm aerial photographs placed 25 cm apart. The micrometer can be read directly to 0.01 mm and estimated to 0.001 mm.

The stereomicrometer allows to point to identical points in the two photos and to measure the horizontal parallax between them. The difference between the horizontal parallax of two sets of identical points can be used to derive the height difference between the two points.

For more details of "plotting with a mirror stereoscope", for example, see pages 158-167 in Schwidewsky, K. (translated by J. Fosberry), 1959. An Outline of Photogrammetry, Sir Isaac Pitman & Sons Ltd, London.

History & comments

Conservation

in custom made box, 354 x 135 x 66 mm

Condition

excellent

Remarks

box marked 21 in paint masking tape, bar engraved "271"

Dates

Catalogued in April 2013 by JMR. Photo by JMR.