ZWO H-Alpha SII OIII Filter Set 31 Mm Unmounted Filters

ZWO H-Alpha SII OIII Filter Set 31 mm unmounted filters includes three narrowband interference filters (H-Alpha 656 nm, S II 672 nm, and O III 501 nm) that block ambient light and capture faint nebulae with high contrast. With a bandwidth of 7 nm, you can capture detailed structures in hydrogen nebulae, planetary nebulae, and supernova remnants, even under urban light pollution.

Key Benefits
✓ Narrowband filters for maximum contrast enhancement in H-Alpha, S II and O III
✓ 7 nm FWHM bandwidth suppresses unwanted light without signal loss
✓ Parfocal design perfectly matches ZWO LRGB and color filters
✓ Unmounted 31 mm filters fit any standard filter wheel
✓ Aluminum housing for secure mounting and minimal reflection

Practical Application
Combine with a monochrome ZWO ASI camera and filter wheel to automatically switch between H-Alpha, S II and O III exposures. Ideal for deep nebula imaging with extra detail and contrast, even under light-polluted night skies.

Technical Specifications
• Format: 31 mm unmounted filters
• Filters: H-Alpha 656 nm, S II 672 nm, O III 501 nm
• Bandwidth: 7 nm (FWHM)
• Transmission: 80%
• Housing: aluminum
• Application: narrowband astrophotography (photographic)