The Baader 2" Narrowband (6.5nm) SII Filter is an excellent choice for astrophotographers who wish to capture the highest contrast images optimized for CMOS, while also performing excellently on CCD at the S-II wavelength. The filters have outstanding light transmission properties in the S-II wavelength range, while completely "cutting off" light at other "undesired" wavelengths. They guarantee excellent results when used with telescopes having a focal ratio of f/10 - f/3.5.
The filters' excellent glass material and craftsmanship promise superb contrast and image sharpness. The coatings are applied to the glass material using the most advanced equipment, ensuring the ideal transmission range. The anti-reflective coatings contribute to excellent imaging, and additionally, the surfaces have been treated to make the glass material scratch-resistant.