This field flattener is an excellent choice for cameras with cropped sensors -- APS-C and smaller. It will not provide a flat field when used with full-frame cameras. The FFEDAPO-01 is designed to work with Explore Scientific's Achromatic Doublet Series (DAR),Essential Series and FCD100 Series telescopes with diameters of 80 mm, 102 mm and 127 mm. The device is threaded so a 2-inch filter can be installed.

A curved focal plane is an inherent feature in most telescope designs and is nothing to note for general stargazers. But, for astrophotographers, the consequences of that same curved plane can ruin hours of patient imaging. Designed for refracting telescopes, Explore Scientific's Field Flattener can tackle the edge-of-field aberrations caused by this necessary curvature to ensure your long night at the eyepiece will not be in vain. This accessory, which now has 55 mm of back focus (+/- 2 mm), offers fully multi-coated optics and slides securely into the 2-inch eyepiece holder.