Skywatcher 0.85x Reduce and Corrector for Evostar-ED72

Skywatcher 0.85x Flattener and Focal Reducer for the Evostar 72 ED Refractor

The corrector was developed for the Evostar 72ED and provides optimal astrophotographic results with this telescope. The focal length is reduced to the factor 0.85x and the field correction is clearly improved at the same time.

The corrector is screwed to the focuser via the M54 thread, thus ensuring optimal mounting without tilting. For attaching a DSLR camera, you need the matching T-ring. We offer T-rings from the M48 connection thread for Sony, Canon EOS and Nikon.

Via individual connection adapters (see accessories section), astro cameras can also be attached. The optimal working distance from the M48x0.85 connection thread of the corrector is 55 mm.

Optional adaption via 2" barrel with the TS2-SKFlat:

This TS Adapter allows the adaption via a 2" barrel, prerequisite is a neat 2" receptacle at your focuser. The adapter provides the following advantages:

You can use 2" filters, the adapter has the matching filter thread at the end of the 2" barrel.

You can rotate the camera and thus optimally match the orientation to the object.

The adapter also allows using the corrector with similar telescopes with 70 mm to 72 mm aperture.

Question:
How do you have to measure the working distance?

Answer from Teleskop-Service:
The working distance is measured from the beginning of the connection thread on the housing of the corrector (see example picture):