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ZWO 2" Duo Band Filter


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  • Efficient and affordable narrowband imaging filter for color cameras.
  • Perfect for beginner narrowband imagers.
  • H-alpha Bandwidth: 15nm.
  • OIII Bandwidth: 35nm.
  • 2-inch Filter Size.


Product Details

  • The ZWO Duo Band Filters are designed to complement their large selection of color cameras. This dual-band filter is perfect for those astronomers who are already imaging using color cameras and don't want to transition to a monochrome camera set, requiring the addition of a filter wheel and narrowband set to complete the system. Be the efficient astronomer with ZWO's Duo Band Filters!

    Efficient Color Camera Imaging

    The ZWO Duo-Band filters are an excellent way for beginning astronomers to dive deep into the realm of narrowband imaging. Along with being focused on the H-alpha and Oiii wavelengths, these filters are also a fantastic solution to dealing with light pollution that is becoming more and more prevalent. On top of this, the Duo-Band filters further improve the contrast and visibility of whichever deep-sky objects you're hoping to image using a color camera. Narrowband imaging doesn't get more convenient than this, especially at such impressive transmission rates of 80% (H-alpha) and 90% (Oiii) for its two bandpasses.

    ZWO Duo Band Filter Transmission Rates

    Designed for Compatibility

    Thanks to the design of these dual-band filters, essentially any camera or filter wheel that is compatible with 1.25-inch or 2-inch filters (depending on which size you purchase) can use these without a problem. 

    Main Features of ZWO Duo-Band Filters

    • H-alpha Bandwidth: 15nm.
    • OIII Bandwidth: 35nm.
    • Made with Schott and Aerometal materials through CNC machining.
    • Extinction treatment to prevent reflection.
    • Dual bandpasses for convenient narrowband imaging.
  • specifications

    Filter ShapeRound
    Filter Thickness1.85mm
    Filter TypeH Alpha
    Filter TypeMultiband
    Filter TypeOIII
    Free ShippingYes
  • included items

    • Efficient and affordable narrowband imaging filter for color cameras.
    • Perfect for beginner narrowband imagers.
    • H-alpha Bandwidth: 15nm.
    • OIII Bandwidth: 35nm.
    • 2-inch Filter Size.


Product Reviews

Customer Reviews
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steven m.

zwo duo filter

I use it with my zwo294mc pro camera it really brings out the color best pictures i have ever taken

United States United States

Not sure

I used it, but there was heavy dew, so I'm not quite sure it works. The image of M33, and M82 looked darker.

OPT Telescopes ZWO 2 Duo Band Filter Review
Blaine G.
United States United States

Better than expected

Cut right through the forest fire haze!

Richard Y.
United States United States

Duo-Band Works Well

I was interested in how effective the Duo-Band filter would be for moonlight imaging. It works very well on H-alpha nebula, allowing much longer, deeper images. The filter improved deepness of OIII objects like M27, but coupled with the ASI2600MC Pro camera, the green side of the nebula's "teal" color is strongest. You can see a comparison image here: . The Duo-Band is very useful at regaining imaging time on moonlit nights.

Nicholas J.
United States United States


This filter is absolutely amazing. I’ve taken some of the best pictures that I’ve ever taken using the ZWO Duo Band filter. Imaging from Bortle class 6 skies with streetlights around you is near impossible. But with the ZWO Duo Band filter, the impossible becomes possible!