The ZWO Duo-Band narrowband filter (1.25") is an affordable solution for those who want to photograph emission nebulae from light-polluted urban environments.
The filter transmits light in two narrow wavelength ranges while blocking the rest of the spectrum. The characteristics of the two passbands are as follows:
- 15 nm bandwidth and 80% transmission in the Hα (656.3 nm) range
- 35 nm bandwidth and 90% transmission in the OIII (500.7 nm) range
The ZWO Duo-Band narrowband filter was designed primarily for ZWO colour cameras, but it also performs exceptionally well with cameras from other manufacturers. The manufacturer's characteristic use of high-quality materials and precision machining are clearly evident in this product as well.