Fixing Field Curvature using Reducer Corrector

I purchased a second hand reducer corrector for my ED80. It cost almost as much as the refractor itself, but its worth it To flatten the field and also to increase your f/ratio, the ED80 offers a dedicated Reducer/Corrector 0.85x. Not only does it lower the f/ratio of the scope from f7.5 to f6.3, but […]