I have just measured the threads on the new Baader MPCC mkIII Coma Corrector.
Front filter: M48 x 0.6
Stopper ring/collar: M48 x 0.6
Removable T2 nosepiece:
Front: M45* x 0.5, Back: M42 x 0.75
(*male measured 44.42mm OD, female 43.96mm ID)
Note on the filter thread, it is 48mm but my thread pitch gauges had a best fit for the 0.6mm pitch rather than the 0.75mm listed in the spreadsheet for 2" filters.
I also note Doug's post (#3) lists 2" filter thread as M48 x 0.6.
Google search is inconclusive, maybe there are two 2" filter threads around?
I saw a thread on CN where someone got an email reply from Orion that their filter threads are M48 x 0.6, so.....