Askar OIII 7 nm 31 mm is a top class filter that transmits light with a wavelength of 500.7 nm emitted by double ionized oxygen atoms, the registration of which is particularly important when photographing emission and planetary nebulae, and so That remnants of supernova explosions.

With an half-bandwidth of just 7 nm, this filter combines the ability to almost completely eliminate the undesirable component from sodium and mercury lamps with high transmission for the OIII spectrum line , one of the most important from the point of view of astrophotography.

Attention! The Askar OIII filter is not recommended for visual observation or for photographing the sun or other objects that do not emit OIII lines.

Highlights of the Askar OIII 7 nm 31 mm filter

• a bandpass filter with a maximum transmission for radiation with a wavelength of 500.7 nm
• Model 31 mm in diameter, rimless
• very narrow half-width of the transmitted band (FWHM = 7 nm)
• OD4 equivalent optical density guaranteeing the effectiveness of cutting out light pollution at the level of 99.99%

Technical specifications

• filter type: bandpass filter
• Filter diameter: 31 mm
• filter thickness: 1.85 ± 0.1 mm
• filter shape: round
• transmitted bands: OIII (500.7 nm)
• location of the maximum permeability peak (CWL): 500.7 ± 1 nm
• Half bandwidth (FWHM): 7 ± 1 nm
• maximum transmission:> 90%
• blocked bands: 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)
• efficiency in blocking light pollution:> 99.99%
• equivalent optical density for blocked lines: OD4 (200 - 1050 nm)
• surface quality index: 60/40
• parallelism: 30 "
• light incidence angle: 0 - 8 °
• frame: absent

Elements of the set

• Askar OIII filter 7 nm 31 mm

guarantee

24 months