The Mewlon-250 CR corrector cuts the coma out and gives a 44 mm flat field for CCD and DSLR users. The corrector is a new baffle hood that should be put in place in the older one. With this corrector, the focal length becomes shorter (2500mm instead of 3000mm). Takahashi also offers dedicated CR-reducer 0.73x and CR-extender 1.5x for this new accessory.
Those new rings have been designed for the TSA-120 refractor. They allow you to put directly the TSA-120 assembly on the M plate. With its bridge plate, this accessory is fine for astrophotography. You can easily put a TGM mount with a guiding scope on the TSA-120 for imaging purposes.
The new CCA-250 replaces the BRC-250 as high diameter astrograph. One aperture of 250mm. Two reducers to transform the original F/5 to F/3.6 focal ratio. Two extenders to transform the F/5 to F/7.5. Three different image circles.More details