Askar Duo-band 1.25 "is the perfect choice for astrophotographers looking for the best compromise between the price and the possibilities and optical parameters of filters.

This filter passes the light emitted by ionized oxygen (OIII) and hydrogen (Hα) atoms. Thanks to the simultaneous exposure in both spectral ranges, it is possible to take great shots with the use of color cameras, without the need for filter wheels or a dedicated set of separate filters.

Attention! The Askar Duo-band filter is not recommended for visual observations. Under no circumstances should it be used as a sun filter.

The most important features of the Askar Duo-band 1.25 "filter

• a filter with a transmittance of more than 95 percent for the OIII and Hα bands
• excellent cutting of the emission lines of mercury and sodium lamps thanks to the high equivalent optical density (OD3)
• Ideal for photographing emission and planetary nebulae

Technical specifications

• filter type: dual-band filter
• filter diameter: 1.25 "
• filter thickness: 1.85 ± 0.1 mm
• filter shape: round
• pass bands: OIII, Hα
• position of the maximum of the transmittance peak for the OIII band (CWL): 495 ± 1 nm
• Half width for the OIII band (FWHM): 30 ± 1 nm
• maximum transmission for the OIII band:> 95%
• position of the maximum transmittance peak for the Hα band (CWL): 656.3 ± 1 nm
• Half width for Hα band (FWHM): 13 ± 1 nm
• maximum transmission for the Hα band:> 95%
• 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:> 99.9%
• equivalent optical density for blocked lines: OD3 (200 - 1100 nm)
• surface quality index: 60/40
• parallelism: 30 "
• light incidence angle: 0 - 8 °
• frame finish: matte black, anodized
• holder thread: M28.5x0.6

Elements of the set

• Askar Duo-band filter 1.25 "

guarantee

24 months