The Duo-Band filter is a narrow band filter passing through two lines - hydrogen (HA) and oxygen (OIII). Designed mainly as an add-on to ZWO ASI color cameras, for astro-amateur who want to use narrowband techniques without having to buy a monochrome camera, filter wheel and narrowband filter kit.
The Duo-Band filter is an economical option for entering narrowband astrophotography, it is also a practical solution to the problem of photography in urban light pollution.
The filter transmits light in the area of the main H-alpha hydrogen line (656 nm) and double ionized O-III oxygen (500 nm), and helps eliminate the influence of moonlight and artificial city light, such as street lighting. It improves the contrast and visibility of numerous deep sky objects, especially emission nebulae, using color cameras.
The Duo-Band filter can be used with all ASI cameras and the EFW electric circular filter. Available in two versions of the luminaire (1.25 inches and 2 inches)
• name: ZWO Duo-Band Filter
• standard (size) of the luminaire: 1.25 "
• line width (FWHM): HA - 15 nm / OIII - 35 nm
• glass foundation: Schott
• transmission> 90% for main OIII lines 486 nm, 496 nm, 501 nm
• transmission> 80% for the HA 656.3 nm line
• optical coatings on both sides of the filter
• thickness: 1.85 nm
• finish: CNC, anodized, laser engraving