With many telescopes, the focal plane is somewhat further out so that photographic use is also possible. However, the problem then arises that certain eyepieces can no longer be focused.
This is only one of the tasks solved by the 2" extension tube.
The advantages in a nutshell:
- High processing quality
- 2'' filter thread
This sleeve bridges the optical path and thus allows to have the focuser in a relatively normal position. The extension sleeve has a very high processing quality. The "optical path" does not include the length of the 2" extension tube, as it disappears into the 2" focuser, for example.