ZWO Duo band 1.25"

ZWO Duo band 1.25"

The 1.25 inch ZWO Duo-Band filter passes H-alpha and OIII light together, allowing a one-shot colour astronomy camera to record emission-nebula signal through two selected bands in the same exposure sequence.

Transmission and contrast

The H-alpha passband is 15 nm wide around 656.3 nm, with transmission above 80%. The OIII passband is 35 nm wide, transmitting more than 90% at 495.9 and 500.7 nm. Suppression outside these bands can improve emission-nebula contrast under unwanted sky illumination.

Optical construction

ZWO specifies 1.85 mm Schott glass, double-sided optical coating, 60/40 surface quality, 1/4-wave optical polish and less than 30 arcseconds parallelism. The CNC-machined cell has an anodised, sandblasted finish and reflection-suppression treatment.

Use and angle limit

Choose the matching filter-wheel or holder size. ZWO specifies approximately perpendicular light or an incidence angle below 8°, and states that this filter is not suitable for wide-angle or ultra-wide-angle camera lenses.

ZWO manufacturer documentation

Compatibility notes

Use the exact named-model manufacturer connection and operating instructions linked with this product. Optional parts and adapters require their specified spacing and power limits.

Additional specifications