This picture above shows the inner- and outermost position.
Variable T-2 extension 20.5mm to 30mm ... for a seamless fine tuning of T-2 distances - always reproducable.
T-2 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 T-2 extension allows to fine tune the distance by the fraction of a mm. The threads (male and female) are the international used T-2 threads (M-42x0,75).
This is how the T-2 extension works:
The three parts (from left to right):
- Base part with long male T-2 thread
- Small counter ring
- Connection part with female T-2 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 extension exactly fitting to your needed length.