Orion Field Flattener for Short Refractors

• Eliminates field curvature in short, optically fast refractor telescopes, for sharper stars
• Designed for use with 400mm to 660mm focal length refractors with f/5 to f/7.5 focal ratios
• Now includes interchangeable male M42 and M48 "wide" thread-on camera adapters (T-ring for your camera sold separately)
• Preserves focal length attributes of the attached refractor telescope while flattening the field of view
• Compatible with 2" focusers and requires 55mm of backfocus

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 in stars 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, stars will 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, 38mm clear 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 only M42 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 adapters come 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 is required to achieve proper focus. This flattener is for photographic use only.

Weighs 7.5 oz.