The use of prisms (monitoring prism) is essential for tachymetric structural monitoring. In order to achieve the highest accuracy in visual and automatic targeting, the prism must be positioned in the center symmetrical point. In our catalogue you will find a large number of different systems for monitoring structures. They make it possible to observe a large number of measuring points at the object to be monitored economically and very precisely in line with the varying requirements.

So far, our building monitoring articles have been used for the monitoring of tunnels, historical buildings, dams, bridges as well as in mining. Practical problems and customer requests lead to a constantly expanding catalogue of accessories for monitoring equipment. We will be happy to help you choose the right products for your needs.

monitoring prism - ball prism - l-bar prism

Bohnenstingl Monitoring Systems

monitoring prism ball prism magnetic base

Monitoring: Magnetic Ball Prism System

  • Two ball prism sizes: Ø30 mm and Ø1.5″ mm
  • Two prism constants available: -11,3 mm and -16,9 mm
  • Two housing materials: Galvanized steel & stainless steel
  • Option: Balls with reflective foil instead of prism
  • Various accessories: Magnetic bases, centering plates etc.
L-Prism Monitoring Prism - L-Bar prism

Monitoring: L-Bar Prism

  • Available with 5 prism constants
  • Connections: Leica socket or M8 threads
  • Sturdy aluminium design
  • Option: L-Bar with reflective foil
sturdy monitoring prism - weatherproof

Monitoring: Sturdy / weatherproof

  • Prism in U-Frame or prism in closed frame
  • Prism constant: -16,9 mm
  • Sturdy aluminium design
  • To screw or glue to object / structure
wall bolt monitoring prism

Monitoring: Prisms vertically above M8 bolt

  • Adapters for all prism types
  • Circular level attached you set prism perdendicular
  • To screw into M8 wall bolts
2018 - Bohnenstingl - Twin-System - Monitoring - Vermessung - Surveying

Monitoring: Twin-Systems
(two monitoring prisms)

  • Use two prisms, but target just one measuring point
  • To use two total station positions to measure one point
  • Two prism constants
  • To screw into M8 wall bolts
L-Bar prism - Cylinder Prism

Monitoring: Cylinder prism
ZP11 on L-Carrier

  • Cylinder prism can be attached just for the measurement period
  • L-Carrier can be mounted by glue, nails or screws
  • Prism can be aligned in any direction while mounting


Our most popular monitoring system is compact, affordable, of high quality and is very flexible.

The ball prism consists of a precisely manufactured steel ball with a glass triple prism mounted exactly in the centre of the ball. On the cylindrical ball base with cone-shaped upper part, the ball prism comes to rest in a forcibly centred position and can be aligned in all directions in a range of more than 180°.
The steel ball is held in place by a permanent magnet integrated in the base. An application on vertical walls and overhead is therefore possible. Depending on the application, the magnet is available with different adhesive forces. A non-magnetic version is also available.

Features of our monitoring system

  • Choice of ball diameter Ø 30 mm & 1.5″
  • Ball prisms with two prism constants available
  • Bases, balls and centering plates alternatively available in stainless steel
  • Bearing of the prism in the centre of the ball with an accuracy of ± 0.2 mm
  • Shock and water resistant


You’ll find our monitoring equipment in the chapter “Monitoring” in our catalog.

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