The Topcon ADS11 Traverse Prism is a robust prism with an effective prism diametre of 64mm and a variable prism constant which can be set changed between 0 and -30mm (absolute).
Topcon ADS11 FAQ
Below is a list of frequently asked questions about Topcon ADS11.
What is the prism constant for the Topcon ADS11?
The absolute prism constant (true value) for the Topcon ADS11 is -30.0mm. The prism constant as defined for Leica instruments for Topcon ADS11 is 4.4mm. For a more detailed explanation on prism constants please see this article.
Can I use the Topcon ADS11 with a Leica instrument?
Yes, you can use the prism with a Leica instrument as long as you set up the correct prism constant in the instrument settings.
What is the prism constant value that I need to use with a Leica instrument?
In order to use the Topcon ADS11 with a Leica instrument you should use 4.4mm as the prism constant value.