Used ZWO 2" Duo-Band Filter


  • Sale
  • $99.95
  • Regular price $149.00

Qualifies for Free Ground Economy Shipping (CONUS Only)

Not Returnable Please note that used items are not returnable.

This is a ZWO 2" Duo-Band filter in excellent condition, with no dust, sleeks, dings.  Comes in its original jewel case.  




ZWO Duo-Band filters are dual narrowband filters that pass light at both H-Alpha (656 nm) and OIII (500 nm) wavelengths. Their main purpose is to augment the performance of ZWO's ASI color cameras. Astronomers who already have an existing One Shot Colour (OSC) camera can now use narrowband techniques for imaging emission objects without having to buy a monochrome camera, filter wheel, and narrowband filter set.

In addition to providing an inexpensive entry point into the field of narrowband imaging, these filters also offer a pragmatic solution for imagers in metropolitan areas with heavy light pollution by minimizing the impact of both natural sources such as moonlight, and artificial sources such as street lamps.

These filters can help improve the contrast and visibility of deep sky objects such as emission nebula when using an OSC camera. An excellent choice for capturing deep objects from locations with heavy light pollution, ZWO Duo-Band filters are compatible with all ASI cameras and EFW Electronic Filter Wheels. This version measures 2" in diameter.

Technical Specifications

  • Filter Size: 2"
  • Thickness: 1.85 mm
  • H-Alpha Bandwidth: 15 nm
  • OIII Bandwidth: 35 nm
  • Surface Quality: 60/40 (Refer to MIL-O-13830)
  • Schott substrate material
  • More than 90% transmission at major OIII line 486 nm, 496 nm, and 501 nm
  • More than 80% transmission at Ha line 656.3 nm

ZWO Duo-Band Filter Highlights

  • Aerometal material with precise CNC machining
  • Fine sandblasting process and anodized finish
  • Extinction treatment to prevent reflection
  • Laser engraving font that will never fade
  • Precise double-sided optical coating
  • Fine-optically polished to ensure accurate 1/4 wavefront and <30 seconds parallelism over the both surfaces