Unlock the full imaging potential of your Vixen SD refractor with the Vixen SD Flattener HD and Reducer HD Kit — a professional-grade accessory bundle engineered for crisp, full-frame astrophotography. Designed specifically for the SD81S, SD103S, and SD115S refractors, this complete kit includes a high-performance field flattener, 0.79× focal reducer, and precisely matched spacer rings, delivering sharp, wide-field images with stunning clarity and contrast.
The SD Flattener HD preserves your telescope’s native focal length while correcting curvature across the field — creating a 44mm flat image circle, ideal for full-frame DSLR and mirrorless cameras. Add the Reducer HD, and you reduce focal length by 0.79× (e.g., f/7.7 becomes f/6.1), all while maintaining that same full-frame coverage. The result? Wide, coma-free deep-sky images with pinpoint stars from edge to edge.
Both components feature Vixen’s ultra-premium AS multi-coating, offering 99.9% light transmission per surface, and a matte-black interior to suppress reflections, ghosting, and flare. Whether you're photographing nebulae, galaxies, or rich Milky Way fields, this kit delivers professional-level imaging performance in a rugged and refined package.
Bonus: The Reducer HD can also be used standalone with the Vixen AX103S and VC200L telescopes, expanding your imaging versatility across multiple OTAs.
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⭐ Features & Benefits
- Precision Matched for Vixen SD Series – Designed for SD81S, SD103S, and SD115S telescopes for optimal back focus and compatibility.
- 0.79× Focal Reduction – Increases field of view while maintaining a full 44mm image circle (perfect for full-frame sensors).
- Built-In Field Flattener – Corrects edge distortion and boosts sharpness across the entire frame.
- AS Multi-Coating – Used in the flagship VSD100 f/3.8 Astrograph, offering over 99.9% light transmission per surface.
- Matte-Black Internals – Suppresses ghosting, reflections, and flare for high-contrast images.
- Supports 52mm Filters – Threaded for standard photographic filters.
- Cross-Compatible – Reducer HD also works with the AX103S and VC200L without the flattener.
- Works with APS-C & Full-Frame Sensors – Optimized for modern DSLR and mirrorless camera systems.
🌌 What It Unlocks
- Sharper star shapes and flatter field across large image sensors
- Expanded field of view with shorter focal lengths
- Elimination of vignetting and field curvature for premium astrophotography
- Compatibility with multiple Vixen telescopes, expanding your imaging toolkit
🎒 What's Included
- Vixen SD Flattener HD
- Vixen Reducer HD
- EX Tube 66
- Spacer Ring for SD81
- Instruction Manual
Specs
| Component | Optical Design | Dimensions (mm) | Weight |
|---|---|---|---|
| SD Flattener HD | 2 elements in 1 group | Φ58 × 34 mm | 111 g |
| Reducer HD | 2 elements in 2 groups | Φ68 × 45.2 mm | 218 g |
| Spacer Ring SD81 | Mechanical adapter | Φ57.5 × 22.5 mm | 18 g |
| EX Tube 66 | Mechanical extension tube | Φ68 × 76 mm | 89 g |
| Coating | AS Coating | Over 99.9% transmission | — |
| Filter Compatibility | — | Accepts 52 mm filters | — |
Warranty
Vixen warranties its products to be free from initial defects in materials and workmanship for a specified period based on part type:
Vixen Electronic Parts: Limited One Year Warranty
Vixen Mechanical Parts: Limited Two Year Warranty