2-inch interface SV550 refractor is compatible with 2-inch and M63*1 accessories. Aazon.co : SVBONY SV550 APO 122 F7 Triplet Apochroatic Refractor... The SV550 122mm telescope adopts a FPL-51 triplet apochromatic lens structure which contains one piece of ED glass. SV209 0.8x reducer/field flattener can correct the defect of field curvature of the user's shooting target, improve the imaging quality and shooting efficiency of the edge.SV209 0.8X focal reducer/field flattener Fully-multi coated All refractors have inherent normal field curvature. Lock screw Tightened screws make the internal structure more stable. In your image, the stars appear sharp and point-like across the field of view. Correction of Field Curvature Defects The SV209 0.8X reducer/flattener is designed for astrophotography with the SV550 122mm f/7 apo refractor, converting the 854mm focal length f/7 refractor into a 683.2mm f/5.6 system for faster wider astronomy and terrestrial photography. The SV550 APO refractor is a compact refractor with 122mm aperture; f/7 focal ratio and 854mm focal length; a great travel telescope for astrophotography and observation; the OTA weighs 6.44kg/ 14.18lb; easy to carry out when fitting into the carrying case You don't have to worry about photos that have a sharp center and blurry edges. In addition to shortening the focal length of the telescope for faster photography, the SV209 0.8X focal reducer/field flattener eliminates the normal field curvature inherent in all refractors. The back focus distance is 55mm, from the shoulder of the reducer to the image plane, the standard distance of the SLR camera body, the reducer/flattener M63*1 thread is screwed into the telescope to ensure a firm connection. This provides images that are sharply focused to the corners of DSLR and CCD imaging chips. One small upgrade, one gaint leap Genuine® - Crankcase Breather Connector SV209 field flattener can correct the defect of field curvature of the user's shooting target; improve the imaging quality and shooting efficiency of the edge of the field of view SV550 122 APO Refractor Telescope - SV209 0.8x Focal Reducer/Field The APO refractor features a 122mm aperture which gathers more light; and offers more clear and detailed images; suitable for deep sky photography and observation; and even some fainter deep sky objects; due to the higher limiting magnitude SV503 70ed SVBONY SV550 APO Telescope, Bundle With SV209 Field Flattener, 122mm F7 Refractor Telescope
