0111
   RANGEFINDER  
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  Surveying Instrument Collection 

Maker

Wild, Heerbrugg (Switzerland)

Model

TM10

Serial Number

905

Dimensions

Base length 800mm

Image

Wild TM10 Rangefinder

Description

Because of its range and its light, robust construction, this Coincidence Rangefinder (Telemeter) is the ideal instrument for a wide range of applications. It is a modular rangefinder with a constant (fixed) base length of 80 cm and measures distances using an optical system. The optics give a large, erect image of the target with a second, smaller, rectangular and inverted partial image in the centre. The coincidence setting screw is then used to displace the inverted image until it coincides exactly with the features in the erect image. The instrument consists of two eyepieces, the righthand eyepiece belonging to the telescope and the lefthand eyepiece is used to read the distance. The convenient combination tripod enables the instrument to be used by the observer from a kneeling or lying position. The horizontal and vertical circle can be read with the vernier to 1/10. The minimum observing range of the instrument is 250 yards.

 

History & comments

Rangefinders were most commonly used in tanks and similar military vehicles for determining distances to targets. The accuracy obtainable by the rangefinder is low - generally not better than about 1/500 at the lower end of its range, and the error increases as the square of the distance - so that its use in surveying is confined to reconnaissance surveys.

Conservation

In a fine wooden box

Condition

Good

Remarks

  • Weight of instrument is approximately 6 kg
  • Instrument donated by the Department of Defence
  • Inscription: D. D. No.12 MK. VII
  • Inscription: D. D. Reg No. B2274
  • Catalogued by T. Ko
  • Updated by F. Pall

Dates

Manufactured in 1943 (approx). Catalogued in 1997

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