Svbony SV209 Field Flattener
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The Svbony SV209 is a 2-inch field flattener and 0.8x focal reducer designed specifically for the SV550 122F7 APO refractor, helping astrophotographers achieve sharp, flat star fields across a full camera sensor. It corrects field curvature and coma while simultaneously reducing focal length to increase imaging speed, making it a practical two-in-one optical accessory. Overall it offers solid optical performance at an accessible price point for amateur deep sky imagers using compatible Svbony refractors.
Key Features & Specs
| Reduction Ratio | 0.8x focal reduction, effectively shortening focal length and increasing field of view for faster imaging |
|---|---|
| Compatibility | Designed specifically for the Svbony SV550 122F7 APO refractor; may work with other similar F7 apochromatic refractors |
| Threading | M63x1 input thread on the telescope side and M48x0.75 output thread for camera-side connection |
| Aperture | 2-inch (50.8mm) form factor to accommodate a wide image circle suitable for APS-C and smaller sensors |
| Optical Design | Multi-element lens group with anti-reflection coatings to minimize chromatic aberration and light scatter |
| Build Quality | CNC-machined aluminum barrel with a durable anodized finish for reliable mechanical alignment |
| Use Case | Optimized for prime focus deep sky astrophotography including nebulae, galaxies, and star clusters |
Best for: Amateur astrophotographers who own the Svbony SV550 122F7 APO refractor and want to improve edge-of-frame star quality while gaining a wider, faster field of view for deep sky imaging.