SVBONY SV220 2" 3 nm H-alpha & OIII Dual Narrowband Filter

The SVBONY SV220 2" dual narrowband filter combines ultra-narrow 3 nm H-alpha and OIII passbands, allowing you to strongly suppress light pollution and sky background while highlighting emission and planetary nebulae. It is specially optimized for full-frame sensors and wide-field optics, delivering uniform illumination from the center to the edge of the frame so that extended nebulae and galaxies are fully captured.
 
Low-halo coating design helps to minimize unwanted glows around bright stars, while the high peak transmission in both H-alpha and OIII bands lets you record a strong, clean signal during long exposures. The filter uses a standard 2" cell with M48×0.75 thread (outer thread) and a mechanical size of 50.8 mm diameter, ensuring broad compatibility with most modern astrophotography cameras and accessories.

Key features

• dual 3 nm narrowband filter for H-alpha and OIII – ideal for imaging emission and planetary nebulae
• full-frame ready and ultra-wide-angle friendly – reduced vignetting and uniform brightness across the field
• low-halo coating design to effectively suppress halos around bright stars
• high average peak transmission (≥85%) in both H-alpha and OIII bands for efficient signal capture
• standard 2" cell with M48×0.75 thread – compatible with mainstream astrophotography equipment
• wide blocking range from 300 to 1050 nm with OD5 average cutoff depth – strong rejection of unwanted wavelengths
• precise surface quality and flatness for sharp, high-contrast images across the whole frame

Technical specifications

• filter type: dual narrowband H-alpha + OIII
• size: 2"
• ring dimensions: Φ50.8 × 7 mm
• thread: M48 × 0.75 mm (single, male thread)
• cell material: 6061T aluminum extrusion
• substrate thickness: 2.0 mm
• clear aperture: 44 mm
• center wavelengths: 500.7 nm (OIII), 656.3 nm (H-alpha)
• peak transmittance: OIII and H-alpha average ≥85%
• bandwidth / FWHM: OIII 3±1 nm, H-alpha 3±1 nm
• blocking range: 300–1050 nm
• blocking depth: average OD5
• surface quality: 60/40
• transmitted wavefront flatness: PV ≤ λ/4
• parallelism: 30″
• net weight: 12.5 g