Askar ColourMagic Duo-Band C2 Filter -SII + OIII - 2" (OPEN BOX)

Designed for deep-sky imaging of emission nebulae with a color camera, the Askar ColourMagic C2 Duo-Band Filter permits both Sulfur II and Oxygen III wavelengths through while blocking those that contribute to light pollution.  The peak transmission is 90% at the center wavelength of 500.7nm and 672nm.  This combination will enhance contrast, darken the background sky, and produce better images of emission nebulae.  

While this filter is similar to the D1 duo-narrowband filter, it is improved as far as peak transmission (90% vs 85%) and filter thickness (2mm vs 1.85mm).

ColourMagic C2 Duo-Band Filter Specifications

FWHM:  OIII = 35nm+/-5nm, SII = 15nm+/-3nm

CWL:  500.7nm & 672nm

Peak Transmittance:  90%

Filter Thickness:  2 +/- 0.05mm

Barrier Property:  OD3 @ 200-1000nm

Surface Finish:  60/40