This 1.25-inch neutral density ND filter is a professional astronomical accessory that attaches to the rear M28.6 thread of standard 1.25" telescope eyepieces. It evenly dims overall brightness without altering color tone, ideal for bright lunar observation and planetary imaging to eliminate overexposure and reveal subtle surface details. Six density options (ND2/ND4/ND8/ND16/ND32/ND64) cover all brightness adjustment demands for lunar and planetary stargazing.
Interface Standard: 1.25 inch, compatible with all 1.25" telescope eyepieces Thread Spec: M28.6×0.6mm standard filter thread Lens Material: High-uniformity acrylic optical sheet Frame Material: CNC machined aluminum alloy Frame Finish: Matte black anti-reflection coating Transmittance of each model:
· ND2: 52% light transmission
· ND4: 25% light transmission
· ND8: 12.5% light transmission
· ND16: 6.25% light transmission
· ND32: 3.12% light transmission
· ND64: 1.56% light transmission
1. Uniform Neutral Density Dimming Evenly attenuates all visible light wavelengths without color cast, suppresses bright lunar glare to bring out faint crater rilles, maria and planetary surface textures without washing out fine details.
2. Six Graduated Density Options
· ND2/ND4: Mild dimming for small aperture telescopes, thin lunar crescent observation
· ND8/ND16: Universal medium density for full moon and Jupiter/Saturn viewing
· ND32/ND64: Heavy dimming for large-aperture scopes, high-magnification planetary shooting
1. Precision Aluminum Filter Frame Lightweight solid aluminum rim with anti-slip knurled edge, smooth M28.6 thread for easy screwing onto eyepiece rear; internal anti-reflection finish blocks stray light flare.
2. Standard 1.25" Universal Thread Perfectly matches all mainstream 1.25-inch astronomical eyepieces with M28.6 rear thread, compatible with H/SR/Plossl eyepiece series.
3. Lightweight Compact Design Thin circular ring structure, does not add extra back focus shift, can stack with other color planetary filters for combined contrast adjustment.
⚠️ This filter CANNOT be used as a solar filter for observing the Sun. Concentrated solar light will melt the acrylic lens and cause permanent eye injury. Only use for night sky observation of Moon, planets and deep-space objects.
· Lunar Observation: Reduce overwhelming full-moon glare to expose delicate crater, mountain and valley details
· Planetary Observation: Dim bright planetary disk for clearer Jupiter bands, Saturn ring divisions and Mars surface features
· Amateur Planetary Astrophotography: Control exposure to avoid overexposed planetary footage
· Light-Polluted Urban Stargazing: Suppress local sky glow for brighter deep-sky targets
1 × Single 1.25" ND filter (optional ND2 / ND4 / ND8 / ND16 / ND32 / ND64)
1. Screw the filter gently onto the rear thread of your 1.25" eyepiece; do not over-tighten to avoid thread damage.
2. Never touch the acrylic lens surface with bare fingers; only clean dust with professional optical lens tissue.
3. Store in dry dust-proof container after use to prevent scratches and surface fogging.
4. Never point the telescope at the Sun with this filter installed, severe eye damage risk exists.