SVBONY SV220 · W9198B · 2″ MOUNTED
Two nebula emission bands. One filter.
Capture H-alpha and OIII together with the SV220 3nm dual-band imaging filter, designed for revealing emission-nebula structure with a colour astronomy camera.
The SVBONY SV220 W9198B is a 2-inch mounted H-alpha and OIII dual-band filter. Its two narrow transmission windows isolate red hydrogen-alpha emission at 656.3nm and blue-green oxygen-III emission at 500.7nm, helping suppress unwanted background light during deep-sky imaging.
What the 3nm dual-band design does
Both emission bands are recorded in the same exposure, making this a practical option for one-shot-colour astronomy cameras. Each window has a nominal 3nm bandwidth; SVBONY specifies a 3 ± 1nm FWHM tolerance. FWHM describes the width of each transmission band at half its peak transmission.
The narrow windows reject much of the surrounding spectrum. This can improve separation between nebular emission and sky background under light-polluted or moonlit skies. Exposure length and total integration time still depend on your telescope, camera, target and conditions.
Choose it for emission nebulae
Use it for objects with H-alpha and/or OIII emission, including emission nebulae, planetary nebulae and supernova remnants. Examples include the Orion, Eagle and Dumbbell nebulae. Their response depends on the emission present in each object.
For galaxies, reflection nebulae and star clusters, a broadband approach generally preserves more of the target’s light and colour. This filter records H-alpha and OIII together; a separate SII dataset is needed for a three-channel SHO image.
Fitting and telescope compatibility
The mounted filter uses a 2-inch M48 × 0.75 thread. Choose a drawer, wheel or holder designed to accept this mounted format and check the available cell clearance before ordering.
SVBONY lists a 44mm clear aperture. Suitability for a larger sensor also depends on filter-to-sensor distance and the telescope’s light cone; a 2-inch filter alone does not guarantee freedom from vignetting.
Fast optics: SVBONY cautions against use at f/5 or faster, including RASA-type systems, because interference-filter band shift can reduce transmission at the required emission lines. Check suitability before selecting this filter for a fast imaging system.
Specifications
| Model / manufacturer SKU | SV220 / W9198B |
|---|---|
| Format | 2-inch mounted imaging filter |
| Passbands | H-alpha 656.3nm and OIII 500.7nm |
| Bandwidth per passband | Nominal 3nm; specified FWHM 3 ± 1nm |
| Mounting thread | M48 × 0.75 |
| Clear aperture | 44mm |
| Out-of-band blocking | Manufacturer-rated average OD5 across the specified 300–1050nm blocking range |
| Primary application | H-alpha/OIII emission-nebula astrophotography with colour cameras |
Version supplied: W9198B, the 2-inch 3nm H-alpha/OIII filter. Check the SKU when comparing other SV220 sizes and bandwidths.
For imaging use. Never use this filter to observe or photograph the Sun without an appropriate dedicated solar filtration system.
Explore our SVBONY telescope filter range, or ask Dark Clear Skies for help matching a filter to your camera and telescope.