Explore Scientific 1.25" 0.9 Neutral Density Filter
If you’ve ever tried observing the Moon through a telescope without a filter, you know just how bright and uncomfortable the view can get—especially during the full Moon phase. The Explore Scientific 1.25" 0.9 Neutral Density Filter is designed to take the edge off that intense brightness, offering a more comfortable and contrast-rich viewing experience for lunar and planetary observers.
This 0.9 density filter transmits roughly 13% of the incoming light, effectively reducing glare without affecting the natural color balance of your target. That’s the key advantage of a neutral density (ND) filter—it dims the image without tinting it. So the Moon still looks like the Moon, not an overly green, red, or blue version of it.
The 0.9 ND level is a sweet spot for those who want significant light reduction without going completely dark. It’s ideal for telescopes with apertures of 6" and up, especially fast scopes that tend to gather a lot of light. Observers using larger Dobsonians or Schmidt-Cassegrains will appreciate how this filter lets them see fine lunar features like rilles, craterlets, and subtle mare differences without eye strain.
The Explore Scientific ND filter screws into any 1.25" eyepiece or accessory that’s threaded for standard filters. The aluminum housing is precision-machined and anodized for durability, and the optical glass is polished and coated to maintain image sharpness and reduce reflections. It comes in a protective plastic case to keep the optics safe when not in use.
While designed with the Moon in mind, this filter also helps when observing bright planets such as Venus or Jupiter. It tones down the brightness just enough to reveal cloud bands or subtle albedo features without sacrificing clarity. It’s also helpful during daylight or twilight observations, particularly of planets near the Sun’s glare.
This is a passive filter—there are no moving parts, no adjustments, just clean optical glass doing its job quietly. If you're after a more customizable solution, you might consider a variable polarizing filter instead, but for simplicity and reliability, a fixed 0.9 ND filter is hard to beat.
The Explore Scientific 1.25" 0.9 Neutral Density Filter is a solid addition to any visual astronomer’s toolkit. It’s small, affordable, and incredibly useful. Whether you’re a casual lunar observer or working through a Moon filter challenge list, this filter will make your sessions more enjoyable and your observations more productive.
Specs at a Glance:
-
Filter Type: Neutral Density (ND)
-
Density: 0.9 (approx. 13% light transmission)
-
Thread Size: 1.25" standard filter threads
-
Optical Glass: High-quality polished and coated
-
Housing: CNC-machined aluminum, black anodized
-
Applications: Moon, bright planets, daylight/twilight viewing
If you’ve got a bright target and tired eyes, this is a simple and effective way to bring balance back to your observing nights.
