The ZWO Duo-Band Filter is a dual narrowband imaging filter designed for one-shot colour (OSC) astronomy cameras. By isolating the important H-alpha (656.3nm) and OIII (500nm) emission lines, it enhances contrast in nebulae while reducing the effects of moonlight and urban light pollution.
Ideal for deep-sky astrophotography, the Duo-Band filter allows colour camera users to capture narrowband-style images without the need for a monochrome camera, filter wheel and multiple filters.
Key Features
- Dual-bandpass design for H-alpha and OIII emission lines
- Improves contrast on emission nebulae
- Reduces light pollution and moonlight interference
- Excellent choice for one-shot colour cameras
- Compatible with ZWO ASI cameras and EFW filter wheels
- Precision optical coatings for high transmission and minimal reflections
Technical Specifications
- Available Sizes: 1.25" and 2"
- Filter Thickness: 1.85mm
- H-alpha Bandwidth: 15nm
- OIII Bandwidth: 35nm
- Schott optical glass substrate
- >90% transmission at OIII wavelengths
- >80% transmission at H-alpha wavelength
- Surface Quality: 60/40 (MIL-O-13830)
Precision Construction
- CNC-machined aerometal housing
- Fine sandblasted and anodised finish
- Anti-reflection extinction treatment
- Laser engraved markings
- Double-sided precision optical coatings
- Optically polished for excellent wavefront accuracy
Important Note
For optimum performance, incoming light should strike the filter as close to perpendicular as possible. This filter is not recommended for use with wide-angle or ultra-wide-angle camera lenses.
Real-World Results
The examples below demonstrate the improvement in nebula contrast and detail when using the ZWO Duo-Band Filter in light-polluted conditions.
