Baader Coma Corrector and Protective T-ring for Canon EOS

[mbalkham]

Tech question here does anyone know if there is a difference between M48 spacer ring (part no. 2458405) recommended in the MPCC Mark III sheet (http://www.baader-planetarium.de/sektion/s30/download/mpcc-mIII-en.pdf) and the S52/M48 adapter ring (http://www.firstlightoptics.com/user/manuals/baader_protectiveT-Ring-CanonEOS-en.pdf) supplied with the protective T-ring for Canon EOS?

I'm trying to insert the MPCC Mark III into the protective t-ring and have not ordered the space ring (http://www.baader-planetarium.de/sektion/s17/bilder/m48-gross-02.jpg). Seems to work physically but might not be exactly the right part, how critical is the 55mm dim?

I don't need (at this stage) anything else in the optical chain (i.e. filters etc.)

Thanks in advance

[Dr_Ju_ju]

I just screw the MPCC direct to the EOS adaptor & then mount on scope...