Askar Ultra E1 duo-band filter has an extremely narrow bandwidth, and an ultra-high transmittance 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, the 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.

The Ultra E filter, as the name suggests, has the "Ultra" halo control capability. During the filter research and development process, we made a special design optimization for Ultra E. And in the end, it became a special filter with one bandwidth at 3nm and the other bandwidth outside 3nm.
When shooting deep-sky galaxies with colour cameras, a duo-narrowband filter in the Hα and OⅢ bands is often used; whereas with a mono camera, a narrowband filter in the Hα, SⅡ and OⅢ bands is often used, leaving users with colour cameras missing one band of nebula detail. This can be compensated by using ColourMagic Ultra E2 Duo-narrowband filter (OⅢ+SⅡ) mentioned above.
ColourMagic Ultra E2 Duo-narrowband filter (OⅢ+SⅡ) has an ultra-high transmittance of over 85% at its center wavelength (500.7nm and 672nm). It can effectively enhance the contrast of your pictures, making it easier to display the details of the stars that otherwise are fairly difficult to spot. In areas with very serious light pollution, this filter can also selectively filter light pollution and cluttered signals through the emission lights of the nebula to achieve the ideal shooting effect.
Technical Specifications
Colour Magic Ultra E1 OIII & Hα
E1 General information table
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FWHM
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HA:3.7nm±0.3nm/OIII:4.0±0.3nm
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CWL
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500.7nm & 656.6nm
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Peak transmittance
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85%
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Thickness
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1.85 ± 0.05mm
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Barrier property
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≥OD5 @ 200-1100nm
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Surface finish
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60/40
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Parallelism
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30″
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