Askar 1X Flattener for 80ED Refractor - 80ED-FLAT1X Field Flattener for the Askar 80ED Refractor OTA This 1X Flattener is specifically designed for the Askar 80ED refractor. Its triplet design (with one element of ED glass) is optimized for APS C. With this flattener installed you will achieve a flatter field and sharper, rounder stars at the edges, as it corrects for both field curvature and coma. The Askar 80ED 1X Flattener does not change the native focal ratio of the 80ED OTA; it remains at f 7.