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SVBONY SV139 1.25-inch ND3.0 Neutral Density Filter
The SVBONY SV139 1.25-inch ND3.0 Neutral Density filter provides an intense 0.1% light transmission (a 10-stop or 1000× reduction) without altering natural color rendition. This specialized filter threads directly into standard 1.25-inch eyepieces and accessories, serving as a light attenuation tool for bright full-Moon views and for use downstream of Herschel solar wedges.
ND3.0 Transmission: Light Reduction for the Full Moon and Solar Wedges
Because an ND3.0 filter cuts 99.9% of incoming light, it is the densest filter in the SV139 range: SVBONY recommends it for observing the full Moon, and it is also used for downstream solar light control. When paired with a Herschel solar wedge (which reflects 95–96% of sunlight away), the SV139 ND3.0 filter safely steps down the remaining intense beam to a comfortable level for white-light solar viewing of sunspots, granulation, and solar faculae.
Multi-Coated Optical Glass in a Standard 1.25" Cell
Constructed with high-quality fully multi-coated optical glass, the SV139 minimizes internal reflections and maintains crisp image contrast. The standard 1.25-inch cell is threaded M28.5 x 0.6mm to fit 1.25-inch eyepieces and accessories.
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What is the main use for an ND3.0 filter in astronomy?
An ND3.0 filter reduces light intensity by 99.9% (transmitting just 0.1%, or a 10-stop reduction). SVBONY recommends it for observing the full Moon, and it is also used in solar observation downstream of a Herschel solar wedge to bring the remaining light down to safe, comfortable visual or photographic levels.
Can I look at the Sun using ONLY this ND3.0 filter on my eyepiece?
NO. NEVER use an ND3.0 filter alone at the eyepiece for solar viewing. Unfiltered sunlight focused by a telescope aperture will instantly shatter or melt an eyepiece filter and cause permanent blindness. An ND3.0 filter must only be used behind a proper front-aperture solar filter or inside a dedicated Herschel solar wedge.
Can I use the SVBONY ND3.0 filter for nighttime viewing of the Moon?
Yes, for the full Moon. SVBONY recommends the ND3.0 for full-Moon observation, when glare is strongest. For other lunar phases, lighter filters like ND0.6 (25% transmission), ND0.9 (12.5% transmission), or ND1.2 (6.25% transmission) are recommended.
How is the ND3.0 filter used with a Herschel Solar Wedge?
A Herschel wedge dumps ~95% of incoming solar energy out of its heat trap, but the remaining 5% light beam is still too bright for direct human eyes. Threading the ND3.0 filter into the wedge's eyepiece barrel reduces that remaining light by 99.9%, bringing the final view into a safe, comfortable intensity range for white-light solar observing.
How do I attach the SVBONY SV139 filter to my setup?
The filter features standard 1.25-inch threads (M28.5 x 0.6mm). It simply threads onto the bottom barrel of any standard 1.25-inch eyepiece, camera nosepiece, or Herschel wedge accessory adapter.
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| Brand |
SVBONY |
| Model |
SV139 |
| Filter Type |
Neutral Density (ND) |
| Optical Density |
ND3.0 (0.1% Transmission / 10-Stop) |
| Barrel Size |
1.25 in (M28.5 x 0.6 Thread) |
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SVBONY SV139 1.25" ND3.0 Filter
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SVBONY 1-Year Warranty
