ZWO narrowband 36 mm (unmounted) NB7nm set of three filters (HSO, SKU: ZWO NB7nmD36)

In response to the growing demand from professional astrophotographers, ZWO has developed an advanced version of narrowband filters specifically designed for capturing images in the HSO color palette.

The filters included in this kit boast exceptional characteristics, including high transmission and an impressively narrow half-bandwidth of only 7 nm. Constructed on a 2 mm thick glass substrate, these filters are coated with a comprehensive multilayer coating for optimal performance.

While narrowband filters are typically employed to enhance contrast between celestial objects and the sky background rather than eliminate light pollution, ZWO's latest filters revolutionize the field by enabling observation and, most importantly, color photography of various nebulae (such as emission, planetary, and supernova remnants) even in highly light-polluted conditions.

It's important to note that for Hα and SII filters, the correct orientation is crucial. The surface with the purple coating should face the camera or camcorder.

Key Features of ZWO HSO 36 mm Narrowband Filters:

• A set of three filters designed specifically for astrophotography in the HSO (HST) palette, offering approximately 90% maximum transmission.

• Half bandwidth of 7 ± 0.5 nm.

• Filters equipped with a full multilayer coating, fabricated on high-quality optical glass substrates that effectively eliminate the undesirable halo effect around stars.

Technical Specifications:

• Filter Type: Rimless Narrowband Filter

• Filter Diameter: 36 mm

• Filter Thickness: 2.0 ± 0.03 mm

• Half Bandwidth (FWHM): 7 ± 0.5 nm

• Maximum Transmission for 656 nm (Hα) line: Approximately 90%

• Maximum Transmission for 672 nm (SII) line: Approximately 90%

• Maximum Transmission for 500 nm (OIII) line: Approximately 90%

• Infrared Blocking Range: 700 - 1100 nm

• Out-of-Band Transmission: Less than 0.1%

• Equivalent Optical Density for Blocked Range: OD3

• Coating Type: Full Multilayer Coating (FMC)

Kit Components:

• ZWO Hα 7 nm Filter

• ZWO SII 7 nm Filter

• ZWO OIII 7 nm Filter

• Plastic Protective Boxes