Askar Colour Magic 2" SII 3nm Filter - CM-SII-3NM-2

For all astrophotography enthusiasts, filters are one of the indispensable accessories to achieve perfect deep-sky imaging. These dedicated astronomy filters for imaging deep-sky objects can effectively eliminate skyglow and other sources of light pollution to enhance contrast and allow the details of your deep-sky target to come through more clearly.  The 3nm Colour Magic Sulfur II narrowband filter is a professional astrophotography tool specifically designed for deep-sky imaging.

The Askar 3nm SII filter has an ultra-high transmittance of over 90% at its center wavelength (672nm). The highly narrow 3nm bandwidth ensures this filter will effectively block out light pollution or other distracting factors such as sky glow. Askar SII filters can effectively capture emission nebulae targets, planetary nebulae and supernova remnants that release SII particles.

The deep red light emitted by SII has a very different character when compared to the light emitted by the surrounding H-alpha.  The filter's 3nm bandwidth and high transmission at the central wavelength enhances the contrast and detail emission nebulae, planetary nebulae and supernova remnants that contain SII.

Colour Magic SII 3nm Narrowband Filter Specifications

FWHM:  3nm

CWL:  672nm

Peak Transmittance:  88%

Filter Optical Thickness:  1.85 mm +/- 0.05 mm

Barrier Property:  OD5 @ 200-1100nm

Surface Finish:  60/40

Filter Size:  2" threaded (50.8 mm)

Parallelism:  30"