Optically fast refractors desirable for astrophotography often suffer from significant field curvature, which is especially noticeable when using CCD imagers with APS-C sized and larger sensors, or DSLR cameras. Orion’s handy field flattener resolves the issue by providing excellent field correction while preserving the focal length attributes of your telescope.
Designed for use with refractors with focal lengths of 400mm to 660mm and focal ratios of f/5 to f/7.5, the Orion Field Flattener for Short Refractors lets you enjoy the full imaging potential of your fast refractor telescope. Fully multi-coated, 38mm clear aperture optics and a glare-reducing threaded interior ensure maximum image contrast.
The Orion Field Flattener for Short Refractors is compatible with 2″ focuser drawtubes and is threaded for use with 2″ filters. Backfocus of 55mm is required.
The Orion T-thread Spacer Ring Kit (sold separately) is recommended to achieve proper distance for use with CCD imagers.
Use with a DSLR only requires a T-ring for the camera (T-ring sold separately).