This picture above shows the inner- and outermost position.
Variable extension 20.5mm to 30mm … for a seamless fine-tuning of T-2/M-48 distances – always reproducible.
The extension tubes are intended for reaching the optimal distances e.g. with correctors, field flatteners, or reducers. They are also needed for eyepiece projection. This variable extension allows us to fine-tune the distance by the fraction of an mm. The threads (male and female) are the international used T-2 threads (M-42×0,75) – M-48.
This is how the extension works:
- Base part with long male T-2 or M-48 thread
- Small counter ring
- Connection part with female T-2 or M-48 thread
Turn the connection part as long until the desired length is reached. Then, tighten the counter ring. Now you have a fixed T-2 or M-48 extension exactly fitting to your needed length.