Svbony S-II SV227 2" 5 nm is a professional astrophotography filter with a half-width transmittance window (FWHM) of 5 nm. It transmits light with characteristic wavelengths of 671.6 nm and 672.4 nm. for ionized sulfur atoms, the registration of which is particularly important when photographing emission nebulae.

This filter combines the ability to almost completely eliminate the undesirable components coming from sodium and mercury lamps with high transmittance for the S-II spectral line, one of the most important from the point of view of astrophotography. It is made on a high-quality optical glass substrate, which guarantees the stability of the filter's operation and its high durability.

Attention! The S-II filter is not recommended for visual or solar observations.

The most important features of the Svbony S-II SV227 2" 5 nm filter

• bandpass filter made on a high-quality glass substrate transmitting S-II band lines
• transmission half width (FWHM) of 7 nm
• high ability to cut out light pollution

Technical parameters

• filter type: band filter
• Filter diameter: 2"
• Optical diameter (filter aperture): 44 mm
• filter thickness: 1.85 mm
• filter shape: round
• passed bands: S-II (671.6 nm; 672.4 nm)
• location of the maximum transmittance peak of the S-II band (CWL): 672 nm
• half bandwidth (FWHM): 5 nm
• maximum transmission for the S-II band: 90%
• blocked bands of light pollution: mercury lamps (435.8 nm, 546.1 nm, 577 nm, 578.1 nm), sodium lamps (598 nm, 589.6 nm, 615.4 nm, 616.1 nm)
• optical density equivalent for blocked lines: OD5 in the range of 300 - 1000 nm
• surface finish quality: λ/4
• parallelism: 30"
• surface quality index: 60/40
• thread: M48x0.75
• weight: 12.5 g

Set elements

• Svbony S-II SV227 2" 5 nm filter

Guarantee

12 months