SVBONY 20mm 66° Ultra Wide Angle Eyepiece - 1.25"
- 20mm Focal Length
- 66° Apparent Field of View
- 1.25" Barrel Size
- 16mm Eye Relief
- 5-Element / 3-Group Optical Design
- Fully Multi-Coated Optics
See exactly what the SVBONY 20mm 66° Ultra Wide Angle Eyepiece - 1.25" shows you, on real sky survey data.
Launch Visual AssistantThe SVBONY 20mm 66° Ultra Wide Angle Eyepiece has a wide 66° apparent field in a standard 1.25" barrel. Its 5-element optical design gives good color correction and contrast, and the comfortable 16mm of eye relief makes it accessible for most observers, including those who wear glasses.
With an apparent field of view of 66°, this 20mm eyepiece offers a more immersive experience than a typical 50° Plössl. This wider field allows you to frame large deep-sky objects like the Andromeda Galaxy (M31) or sprawling open clusters within a single view, providing valuable context for your observations.
The optical path consists of 5 lens elements arranged in 3 groups, a design for good color correction and contrast. All optical surfaces are fully multi-coated with a broadband green coating to maximize light transmission. To further enhance contrast, the interior of the housing and the edges of the lenses are blackened to minimize stray light and internal reflections.
A generous 16mm of eye relief is particularly helpful for eyeglass wearers. The eyepiece includes a folding rubber eyecup to help position your eye and block ambient light. The aluminum housing features a two-step anodized matte finish to reduce glare, and the 1.25" barrel is threaded to accept standard astronomy filters.
The primary advantage is the 66° apparent field of view, which is substantially wider than the ~50° field of most kit Plössl or Kellner eyepieces. This provides a more expansive, "spacewalk" feeling and makes it easier to frame large celestial objects.
In a 6" f/8 Dobsonian (1200mm focal length), this 20mm eyepiece will provide 60x magnification. The 66° field gives about 1.1° of true field, enough to frame the bright core of the Orion Nebula around the Trapezium together with much of its surrounding nebulosity.
Yes, 16mm of eye relief is generally considered comfortable for most eyeglass wearers. Fold the rubber eyecup down and keep your glasses on; whether you see the very edge of the field depends on your frames.
Whether the entire Pleiades cluster fits depends on your telescope's focal length. The Pleiades span almost 2°. The true field is about 66° divided by the magnification, so in telescopes of roughly 500mm focal length or less (25x or lower) the whole cluster fits. In longer instruments like an 8" SCT you see the brightest core stars.
The blackened interior and lens edges absorb stray light that might otherwise bounce around inside the eyepiece. This prevents internal reflections from washing out the image, resulting in a darker sky background and higher contrast, which helps faint details on planets and nebulae stand out more clearly.
Yes, the 1.25" barrel of the SVBONY 20mm eyepiece is threaded to accept all standard 1.25" astronomy filters, such as moon filters, light pollution filters, and color planetary filters.
| Brand | SVBONY |
| Model | F9157D |
| SKU | SV-F9157D |
| Focal Length | 20mm |
| Apparent Field of View | 66° |
| Barrel Size | 1.25" |
| Eye Relief | 16mm |
| Optical Design | 5 elements in 3 groups |
| Coatings | Fully multi-coated (broadband green) |
| Filter Threads | Standard 1.25" |
| Housing | Aluminum, two-step anodized matte finish |
| Interior | Blackened to reduce reflections |
| Eyecup | Folding rubber eyeguard |
SVBONY 20mm 66° Ultra Wide Angle Eyepiece - 1.25"
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