ZWO H-Alpha SII OIII filter set 31 mm loose filters

ZWO H-alpha, SII and OIII filter set 31 mm: narrowband photography in the Hubble palette

This set of three separate 31 mm narrow band filters isolates the emission lines of hydrogen (H-alpha, 656 nm), sulfur (SII, 672 nm), and oxygen (OIII, 501 nm). With a half-life of 7 nm, virtually all ambient light is suppressed, allowing faint nebula structures to land on the sensor with contrast, even from light-polluted areas or in moonlight.

You can combine the three channels in editing software into the classic Hubble palette (SHO). Because the filters are homophotic with the ZWO LRGB filters, you can switch between them without having to refocus: ideal for automatic sessions with a filter wheel.

Features

• Three narrow-band filters with 7 nm full width at half maximum
• Suppresses light pollution and moonlight almost completely
• Parfocal with ZWO LRGB filters: no refocusing
• Single 31 mm filters for standard filter wheels

Compatibility

Fits filter wheels with 31 mm slots. Intended for monochrome ZWO ASI cameras; combine with a ZWO EFW filter wheel for automatic filter changes.

Specifications

The 31 mm narrow band set from the filter series of ZWO. If you are working with a larger sensor, choose the 36 mm version.