Skywatcher 1.25" focuser adaptor

[mswhin63 (Malcolm)]

Hi All,

My skywatcher DOB has as standard a 1.25" adaptor. The 1.25" barrel can unscrew leaving 2 threads and the focuser wedge. One is a T-thread for imaging.

Can anyone suggest the internal thread name or dimensions are?

I will try and get some images later if needed.