Askar Colour Magic 2" Duo-Narrowband 3nm Filter - Ha & OIII - CM-DUO-3NM-2

Designed for deep-sky imaging of emission nebulae, the Askar 2" Colour Magic Duo-Narrowband 3nm Filter permits both H-alpha and Oxygen III wavelengths through while blocking those that contribute to light pollution.  The peak transmission is 88% 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, supernova remnants & planetary nebulae.

ColourMagic Duo-Narrowband Filter Specifications

CWL:  500.7nm & 656.6nm

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"