Description
Optically fast refractor telescopes used for astrophotography are often plagued by significant field curvature, which is especially noticeable when using CCD/CMOS imagers and DSLRs with APS-C sized and full-frame sensors. This manifests instars that are out of focus on the periphery of the image frame. Orion's handy field flattener solves this problem by providing excellent field correction while preserving the focal length attributes of your telescope. With the field flattener, starswill appear in sharp focus across the entire frame.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, 38mmclear aperture optics and a glare-reducing threaded interior ensure maximum image contrast.We've upgraded the design of the Orion Field Flattener for Short Refractors to accommodate interchangeable thread-on camera adapters. And now we include both male M42 (standard T thread) and M48 (wide T thread) camera adapters (previously included onlyM42 adapter). The M48 adapter is recommended for use with full-frame camera sensors. Depending on which adapter you use, you will need the corresponding T-ring (M42 or M48) for your specific camera model (sold separately).Both the M42 and M48 adapterscome with a thread-on aluminum cap.The Orion Field Flattener for Short Refractors has fully multi-coated 2-element optics and a clear aperture of 38mm. It is compatible with 2" focuser drawtubes and its barrel is conveniently threaded for use with 2" filters. Backfocus distance of 55mm isrequired to achieve proper focus. This flattener is for photographic use only.Weighs 7.5 oz.
