SVBONY SV227 2″ OIII 5nm Narrowband Filter

Product Overview

The SVBONY SV227 OIII is a 2″ narrowband imaging filter with a 5 nm passband centred on the 500.7 nm doubly ionised oxygen line. Peak transmission is at least 90%, blocking is ≥OD5 across 300–1000 nm, and SVBONY's spec table gives a 44 mm clear aperture. The 1.85 mm substrate sits in a CNC-machined, sand-blasted, black-anodised cell with an M48 x 0.75 thread, and SVBONY lists the net weight as 12.5 g.

Who It's For

This is a good match if you image planetary nebulae, supernova remnants and emission nebulae with a monochrome camera, for HOO bicolour or full SHO, from a 2″ filter wheel or drawer.

Key Features & Design

• 5 nm at 500.7 nm: isolates OIII emission and raises target-to-sky contrast under urban skies.
• ≥90% peak transmission and ≥OD5 blocking from 300 to 1000 nm.
• Infrared blocked: roughly 700–1100 nm is rejected, so no separate IR-cut filter is needed.
• Ion-assisted multi-coating on German glass for scratch resistance and wavelength stability.
• Metal cell: CNC-machined, sand-blasted, black-anodised and laser-engraved.

Optical Design

OIII emission sits close to the brightest part of the light-pollution spectrum, which is why a narrow passband matters most here. At 5 nm, with ≥OD5 rejection elsewhere, the filter records the 500.7 nm line with a dark background, and the deep blocking also removes the near infrared. Surface quality is 60/40, with 1/4λ surface parallelism and 30″ parallelism.

Recommended Uses

• OIII imaging of planetary nebulae and supernova remnants.
• HOO and SHO imaging alongside H-alpha and SII filters.
• Deep-sky imaging from light-polluted urban areas.

Compatibility and Accessory Notes

• Thread: M48 x 0.75, single thread, standard 2″ size.
• Holders: 2″ filter wheels, filter drawer sliders and 2″ nosepieces.
• Matching filters: SVBONY makes the SV227 2″ H-alpha and SII 5 nm filters and a 2″ SHO set.

Good to Know Before You Order

• Focal ratio: SVBONY lists it as unsuitable for telescopes faster than f/4.
• Not for solar use.
• This listing is the filter only; SVBONY also offers it with a 2″ holder.

Frequently Asked Questions

Is it difficult to set up?

No. It threads into a 2″ filter wheel position, drawer slider or nosepiece like any standard M48 filter.

Is it a visual OIII filter?

It is designed as an imaging filter; its 5 nm passband is narrower than typical visual OIII filters.

Do I need an IR-cut filter as well?

No. The filter blocks the near infrared on its own.

Bottom Line

In short: a 2″, 5 nm OIII filter at 500.7 nm with ≥90% peak transmission and ≥OD5 blocking, for nebula imaging at f/4 and slower.