Designed for deep-sky imaging with color astro cameras, the Ultra E1 filter, as the name suggests, includes "Ultra" halo control capability. Askar Ultra E1 duo-band filter has an extremely narrow bandwidth, and an ultra-high transmittance of over 85% at its center wavelength (500.7nm and 656.6nm). It can effectively eliminate the influence of light pollution. Even if you are in an area seriously affected by light pollution, pictures taken with the ColourMagic Ultra E 2” Duo-narrowband Filter are still very good. It is so practical and efficient that you can get astronomical images of high quality with just one duo-band filter and an ordinary astronomical colour camera. The ColourMagic Ultra E 2” Duo-narrowband Filter is ideal for photographing emission nebulae, planetary nebulae or supernova remnants. The highly narrow bandwidth of the filter effectively blocks out the effects of light pollution or other distracting factors such as night glow. ColourMagic E1 Ultra Duo-Band Filter Specifications FWHM: OIII = 4.0 +/- 0.3nm, Ha = 3.7nm+/- 0.3nm CWL: 500.7nm & 656.6nm Peak Transmittance: 85% Filter Thickness: 1.85 +/- 0.05mm Barrier Property: ≥OD5 @ 200-1000nm Surface Finish: 60/40 Parallelism: 30"
