In order to guarantee the accuracy of the prism constants, we measure each triple prism individually and install it in the steel ball.
To examine the accuracy of the prism constant and the position of the central reflection point, we have our spherical prisms tested by the Karlsruhe Institute of Technology (KIT).

For this purpose, ball prisms are taken from the current series and a unique serial number is engraved into each ball socket. They are then measured by the KIT. As a result, a test certificate is issued for each prism with serial number.
Since then, the deviations from the nominal values have been better than +-0.1 mm for 90% of the test specimens. The maximum deviation was 0.3 mm.
The test certificate refers to the ball prism whose serial number is engraved on the back of the ball. In addition to the prism constant K , which was determined from several comparison measurements for a high-precision reference prism, the position of the centre of the prism relative to the centre of the ball is also indicated.

How to purchase a tested ball prism

Would you like to buy one or more tested ball prisms? Simply send us an email, stating the desired article number. If you want to check if the tested ball prisms are in stock at the moment, you can take a look at the availability in our online shop.    info@bohnenstingl.de