Askar ColourMagic Duo-Band C1 Filter - Ha + OIII - 2"

Designed for deep-sky imaging of emission nebulae with a color camera, the Askar ColourMagic C1 Duo-Band Filter permits both H-alpha 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 656.6nm.  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 C1 Duo-Band Filter Specifications

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

CWL:  500.7nm & 656.6nm

Peak Transmittance:  90%

Filter Thickness:  2 +/- 0.05mm

Barrier Property:  OD3 @ 200-1000nm

Surface Finish:  60/40