Field Flatteners, Focal Reducers & Coma Correctors
Field flatteners and coma correctors are essential accessories for sharp, professional-looking astrophotography. Most telescopes produce a slightly curved focal plane or, in the case of fast Newtonian reflectors, coma that stretches stars into comet-like shapes toward the edges of the image. These correctors reshape the light so stars stay round and pinpoint from the center of the frame all the way to the corners.
This collection includes Explore Scientific field flatteners and focal reducers designed for our ED APO refractors, which flatten the field and, in reducer versions, speed up the focal ratio for shorter exposures and a wider field of view. It also includes coma correctors for Newtonian telescopes used in astrophotography. Pairing the right corrector with your telescope and camera is one of the most important steps in producing clean, detailed images of nebulae, galaxies and star clusters.
Choosing the right corrector depends on your telescope design and focal ratio. Refractor owners typically use a field flattener, or a combined flattener and reducer, while Newtonian owners use a coma corrector. Correct back focus spacing between the corrector and the camera sensor is critical, and Explore Scientific T-rings, camera adapters and extension rings make it easier to achieve. Many of these correctors also improve visual observing with wide-field eyepieces. For anyone serious about astrophotography, a matched corrector is often the single most important upgrade after the telescope and mount.
