SVBONY SV227 OIII 5 nm 2" filter (SVBONY, SKU: W9187DC) is a narrowband emission filter designed for nebula astrophotography. Its 5 nm bandpass, centred at 500.7 nm, isolates the ionised oxygen O III emission line, increasing the contrast of emission nebulae, planetary nebulae and supernova remnants against the sky background. The filter reduces the transmission of artificial lighting and natural skyglow outside the relevant band.

Key features

• narrow 5 nm O III bandpass centred at 500.7 nm
• peak transmittance of at least 90%
• out-of-band blocking of at least OD5
• increased contrast of objects emitting radiation in the O III band
• infrared blocking within the 700–1100 nm range according to the manufacturer
• multilayer coatings applied using IAD technology for increased surface durability and central-band stability
• metal, CNC-machined and black-anodised cell with an M48 × 0.75 thread

Set elements

• one SVBONY SV227 OIII 5 nm 2" filter
• one protective PP plastic box

Technical specifications

• manufacturer: SVBONY
• model: SV227
• SKU: W9187DC
• type: narrowband O III emission filter for astrophotography
• cell size: 2"
• central wavelength: 500.7 nm
• FWHM bandwidth: 5 nm
• peak transmittance: ≥90%
• specified wavelength range: 300–1000 nm
• out-of-band blocking: ≥OD5
• declared infrared blocking: 700–1100 nm
• clear aperture: 44 mm
• optical substrate thickness: 1.85 mm
• optical material: optical glass
• coatings: multilayer, applied using IAD technology
• surface scratch-dig quality: 60/40
• surface flatness: 1/4 λ
• surface parallelism: 30 arcseconds
• cell material: metal
• cell finish: CNC machining, sandblasting, black anodising and laser engraving
• mounting thread: M48 × 0.75
• thread design: single mounting thread
• compatible telescope focal ratio: f/4 or slower
• net weight: 12.5 g
• usage restriction: the filter is not intended for observing or photographing the Sun

The narrow transmission band and effective out-of-band blocking make the filter suitable for recording nebular structures emitting light in the O III line, including under an elevated sky-background brightness.