SVBONY SV220 2″ 3nm H-Alpha & OIII Dual Narrowband Filter

Product Overview

The SVBONY SV220 2″ 3nm is a dual narrowband filter with 3 ±1 nm passbands on OIII (500.7 nm) and H-alpha (656.3 nm), average peak transmittance of 85% or more in both bands, and average OD5 blocking from 300 to 1050 nm. The 2.0 mm substrate has a 44 mm clear aperture, 60/40 surface quality, transmitted wavefront PV ≤ λ/4 and 30″ parallelism, mounted in a 6061T aluminium cell (Φ50.8 x 7 mm) with a single M48 x 0.75 male thread. Net weight is 12.5 g.

Who It's For

This is a good match if you image emission nebulae with a large-sensor colour or mono camera, up to full frame, from a light-polluted site and want the contrast of 3 nm passbands across the whole field.

Key Features & Design

• 3 nm H-alpha and OIII passbands: isolate the emission lines tightly for high contrast under bright skies.
• ≥85% average peak transmittance: keeps integration times practical.
• Minimal-halo multi-layer coating: reduces glare and halos around bright stars for cleaner colour.
• 44 mm clear aperture: SVBONY rates it full-frame compatible and suitable for ultra-wide-angle lenses with reduced vignetting.
• Standard 2″ cell: M48 x 0.75 thread.

Optical Design

Narrowing each passband to 3 nm keeps the nebula's line emission while admitting less than half the sky background of a 7 nm filter, so the background darkens and the target stands out. The multi-layer coating is designed to minimise the reflections between filter and sensor that cause halos around bright stars, a common issue with narrowband filters. The 44 mm aperture gives even illumination across a full-frame sensor.

Recommended Uses

• Large emission nebulae on full-frame and APS-C sensors from urban and suburban sites.
• Moonlit nights: narrow passbands extend usable imaging time.
• Bicolour Ha/OIII imaging with a colour camera, or combined data with a mono camera.

Compatibility and Accessory Notes

• Mounting: M48 x 0.75 male thread for 2″ nosepieces, filter drawers, filter wheels and M48 imaging trains.
• Sensors: 44 mm clear aperture, full-frame compatible per SVBONY.
• Optics: tight passbands are best matched to moderate focal ratios. Send us your telescope and camera and we will confirm the fit.

Good to Know Before You Order

• Imaging filter: it has no application in visual observing.
• Emission targets: galaxies and reflection nebulae gain little from narrowband filtering.
• Exposure: 3 nm passbands call for longer sub-exposures than a 7 nm filter on the same target.

Frequently Asked Questions

Is it difficult to set up?

No. It threads onto any M48 x 0.75 nosepiece, drawer or wheel like a standard 2″ filter.

Will it cover a full-frame sensor?

SVBONY specifies it as full-frame compatible, with a 44 mm clear aperture.

3 nm or 7 nm?

3 nm gives higher contrast under bright skies; 7 nm collects signal faster and is more forgiving on very fast optics.

Bottom Line

In short: a 2″ 3 nm H-alpha and OIII dual narrowband filter with a 44 mm full-frame aperture, minimal-halo coating and OD5 blocking for high-contrast nebula imaging from bright skies.