Review on Celestron C Series Telescope f/6.3 Reducer Corrector by Larry Lackings

You get a nice bright and flat center, but the vignetting and curved stars at the edges are insane for the price you pay. I use this in the C8-XLT with Canon M50 ASP-C. I usually end up cropping out most of the image due to the curvature of the field at the edges. If it weren't for the extra brightness, I'd probably just stick with the original focal length and f-factor. I also use OAG and the stars in the OAG camera are curved too. To answer other questions, I have my back focus at exactly 105mm. I machined my T bayonet mount to the nearest thousandth to match my OAG exactly in the optical chain. Do a little research and save up for a nicer one if you don't want to crop most of your photos. Good for small galaxies and beyond, but terrible for a wide field.