Orion 8893 Field Flattener for Short Refractors

• Eliminate field curvature in short, optically fast refractor telescopes with this handy 38mm clear-aperture, fully multi-coated field flattener
• Designed for use with 400mm to 650mm focal length refractors with f/5 to f/7.5 focal ratios
• Optimizes your fast refractor telescope for astrophotography
• Preserves focal length attributes of the attached refractor telescope while flattening the field of view
• Requires 55mm of refractor telescope back focus, weighs 7.5 oz.

• Item Reference: B004SFLCLO 0759270088934 759270088934