Orion Field Flattener for Short Refractors 8893

Optically fast refractor telescopes used for astrophotography are often plagued by significant field curvature, which is especially noticeable when using CCD imagers with APS-C sized and larger sensors, or DSLR cameras. Designed for use with refractors with focal lengths of 400 mm to 650 mm and focal ratios of f/5 to f/7.5. Fully multi-coated, 38 mm clear aperture optics and a glare-reducing threaded interior ensure maximum image contrast. Backfocus of 55 mm is required.